BMW F85 X5 M and F86 X6 M — Best Upgrades Guide

The BMW F85 X5 M and F86 X6 M occupy a unique position in the performance car landscape. They are full-size SUVs producing 575bhp from the S63 twin-turbocharged V8 — cars that can carry five adults and their luggage in genuine luxury while covering 0-62mph in under 4.2 seconds and lapping circuits at speeds that embarrass dedicated sports cars costing considerably more. They are, in every meaningful sense, the original super SUVs — the cars that proved the concept before Lamborghini's Urus, Porsche's Cayenne Turbo GT, and Aston Martin's DBX made it fashionable.

The F85 and F86 were produced from 2015 to 2019 and have aged exceptionally well — both in terms of their performance credentials and their visual presence. On the used market they represent one of the most compelling value propositions in the performance car world — enormous performance, genuine daily usability, and a well-developed aftermarket at prices significantly below their original retail cost.

This guide covers the best upgrades available for the BMW F85 X5 M and F86 X6 M — two cars that respond to the right modifications more dramatically than their size might suggest.

Understanding the F85 and F86 as Platforms

The F85 X5 M and F86 X6 M share their S63 V8 engine and most mechanical architecture — the same twin-turbocharged 4.4-litre unit that powered the F10 M5 and F12/F13 M6, producing 575bhp and 750Nm of torque in this application. The S63 is one of BMW's most celebrated performance engines and one of the most thoroughly validated tuning platforms in the high-performance car world.

The F85 and F86 differ in body style — the X5 M is a traditional five-door SUV with a more upright roofline and greater load space, while the X6 M is a four-door coupe SUV with a sloping roofline that creates a more dramatic silhouette at the cost of rear headroom and boot space. Both share the same front bumper, mechanical architecture, and most exterior body components — meaning the aftermarket upgrade path is largely identical between the two models.

The F85 and F86 are the predecessors to the current G05 X5 M and G06 X6 M — a distinction that is relevant for parts buyers, as the F-series and G-series models have different body geometry that means exterior parts are not interchangeable between generations.

Carbon Fiber Front Splitter and Aero Upgrades

The F85 X5 M and F86 X6 M front ends are among the most aggressive on any BMW of their era — the wide lower intake, the prominent M-specific bumper, and the car's considerable frontal area create a front profile that looks genuinely imposing. A carbon fiber front splitter addition builds on this foundation, extending the lower bumper line and adding visual mass to the front end that grounds these large vehicles and gives them a more planted, performance-oriented stance.

Front splitter upgrades on the F85 and F86 serve a different visual purpose than on lower sports cars. On a car of this size and height, a carbon splitter creates a visual connection between the front bumper and the road surface that reduces the apparent ride height and makes the car look lower and more aggressive than its SUV proportions suggest. This visual lowering effect is one of the most effective transformations available for these models.

Carbon fiber front lip additions — more modest than a full splitter — are also available for the F85 and F86 and deliver a subtler visual enhancement that suits owners who want a refined rather than aggressive upgrade direction. For X5 M owners who use their car primarily as a luxury daily driver with occasional performance use, a front lip is a more appropriate choice than a full aggressive splitter.

Side skirt extensions on the F85 and F86 are proportionally very impactful given the cars' considerable flank length. Carbon fiber or gloss black side skirt additions create a visual lowering effect along the car's lengthy sill section that dramatically improves the stance — making these tall SUVs appear more planted and more connected to the road surface than their factory ride height creates.

Carbon Fiber Rear Diffuser and Boot Spoiler

The F85 X5 M and F86 X6 M rear ends feature the same quad exhaust arrangement that distinguishes M-division BMW products — twin pipes on each side creating a visual symmetry that carbon fiber diffuser upgrades exploit naturally. A carbon diffuser replacement for the F85 or F86 transforms the lower rear bumper section significantly — adding visual depth and a race-derived aesthetic that references the S63's performance credentials more directly than the factory item.

The F86 X6 M's sloping roofline creates a natural aerodynamic opportunity at the rear — a carbon fiber boot lid spoiler addition follows the X6's roofline angle and adds visual punctuation to the rear profile that emphasises the X6's coupe-inspired silhouette. This is one of the more impactful single exterior upgrades available for the X6 M and one that suits its distinctive body shape particularly well.

For X5 M owners, a more subtle rear spoiler addition at the top of the tailgate creates a cleaner visual finish to the rear profile without conflicting with the more upright roofline that defines the X5's character.

Exhaust Upgrades — The S63 Unleashed

The S63 V8 in the F85 and F86 is an outstanding engine whose factory exhaust is, like all BMW M car exhaust systems of this era, significantly restricted by noise regulation requirements. The potential acoustic character of a 575bhp twin-turbocharged V8 in a large SUV is extraordinary — and the factory exhaust system prevents most of it from being heard.

A valved cat-back exhaust system is the most impactful and most practical exhaust modification for the F85 and F86. In closed mode it remains quiet enough for the luxury daily driver role these cars frequently fulfil. In open mode the S63 reveals a deep, authoritative V8 character that is entirely disproportionate to the car's SUV body — a sound that makes absolutely clear that this is not a standard X5 or X6.

The contrast between the F85 and F86's luxury SUV character and the S63's full acoustic presence in open exhaust mode is one of the most entertaining aspects of owning these cars. A quality valved exhaust system makes this contrast permanently available on demand — closing the valves for school runs and residential areas, opening them for motorway on-ramps and track days.

High-flow sports cat downpipes for the S63 in the F85 and F86 deliver the same meaningful power gains as on other S63-powered BMW M cars — 80–100bhp on a quality remap with supporting modifications. For F85 and F86 owners who want to transform the performance as well as the sound, downpipes and a remap represent the highest value performance modification available — turning already rapid cars into something that defies their size and weight even more completely.

Suspension Upgrades — Managing the Size

The F85 X5 M and F86 X6 M's factory suspension is genuinely impressive given the challenge of making a car of this size and weight handle like a performance car. The adaptive air suspension standard on these models manages body movement effectively and provides the dual character — comfortable luxury cruiser and rapid performance machine — that defines these cars.

Lowering the F85 and F86 through the factory air suspension's adjustment range is available and improves the visual stance meaningfully — but the factory system's adjustment range is limited, and owners who want a more dramatically lowered stance need aftermarket solutions.

Aftermarket air suspension upgrade kits for the F85 and F86 provide a wider adjustment range than the factory system — allowing both a lower static stance and a more aggressive suspension tune at lower settings. For owners who want the visual benefit of a significantly lowered ride height combined with the everyday usability of air suspension's raise function, an aftermarket air suspension upgrade is the most practical solution.

Coilover conversion kits are available for the F85 and F86 for owners building track-focused versions of these cars — a niche but enthusiastic community that has proven these large SUVs are genuinely capable circuit vehicles when properly prepared. Track coilover setups on the F85 and F86 require spring rates calibrated for the car's significant kerb weight — the spring rate appropriate for a BMW M3 is wholly inadequate for a car that weighs nearly twice as much.

Geometry adjustment on the F85 and F86 delivers meaningful improvements in cornering behaviour — additional front negative camber reduces understeer and improves front grip in a way that is immediately apparent on a car of this size. A professional geometry setup after any suspension modification is as important on these large M cars as on their smaller siblings.

Wheel Upgrades

The F85 X5 M and F86 X6 M use the 5x120 bolt pattern on the front axle and a wider rear track — always verify front and rear wheel specifications separately when ordering aftermarket wheels for these models, as the staggered fitment configuration requires different front and rear specifications.

Wheel upgrades on the F85 and F86 need to account for the cars' significant weight and the load ratings required by vehicles of this mass. Lightweight forged wheels deliver meaningful unsprung weight reduction — particularly significant on cars this heavy, where unsprung weight reduction has a proportionally greater effect on handling than on lighter cars. Always verify load rating compatibility when selecting aftermarket wheels for these models.

The F85 and F86's wide arches accommodate significantly larger wheel and tyre combinations than the factory specification — for owners building a stance-focused build, aftermarket wheel and tyre packages in aggressive widths fill the arches dramatically and transform the cars' visual presence from imposing to extraordinary.

Interior and Detail Upgrades

The F85 X5 M and F86 X6 M interiors are among the most well-equipped and premium environments in any BMW M car — the combination of luxury SUV specification and M-division performance focus creates a cabin that is both more comfortable and more feature-rich than the dedicated sports cars in BMW's range. Carbon fiber interior upgrades on these cars therefore serve a different purpose than on a track-focused M3 or M4 — they add performance-oriented visual character to an already premium environment rather than replacing luxury materials with racing ones.

Carbon fiber trim inserts for the F85 and F86 dashboard, centre console, and door cards are available and create a more overtly performance-focused cabin character that complements the cars' external modifications. Combined with the exterior carbon aero package, a full carbon interior treatment on the F85 or F86 creates a comprehensive visual statement from every angle — inside and out.

The F85 vs F86 — Which Is the Better Build?

The choice between building an F85 X5 M or an F86 X6 M depends primarily on the intended use rather than any meaningful performance difference — the mechanical specification is essentially identical between the two.

The F85 X5 M is the more practical choice for owners who need genuine five-seat capacity with maximum boot space and the ability to tow. Its more upright roofline creates better rear headroom and a more useable load area — and its more conventional SUV proportions suit subtle, understated build directions more naturally than the more dramatic X6.

The F86 X6 M is the more visually dramatic choice. Its sloping roofline, more sculpted flanks, and coupe-inspired silhouette create a more distinctive presence than the X5 — and its proportions respond more naturally to aggressive aero additions. For owners whose primary motivation is visual presence and driving character over practicality, the X6 M's more dramatic starting point makes it the more compelling build foundation.

Both cars are outstanding platforms. Both deliver the same S63 performance and the same modification potential. The choice between them is a matter of proportion and lifestyle rather than capability.

At Velocity Car Parts all BMW F85 X5 M and F86 X6 M parts are verified for chassis-specific fitment and backed by our fitment guarantee. Browse our BMW F85 collection and BMW F86 collection and build your M SUV with confidence.