AST x MOTON Coilovers — BMW Z4 G29 & Toyota GR Supra A90

The Shared Platform — Why One Page Covers Both Cars

The BMW Z4 (G29) and Toyota GR Supra (A90) share a platform. Same chassis, same suspension geometry, same B58 straight-six (in M40i / A90 3.0L trim), same front and rear caliper mounting points. The two cars were co-developed at BMW's Dingolfing plant, with final assembly for the Supra handled by Magna Steyr in Austria. That's why the brake catalogue already treats them as one fitment — DIXCEL's 348×36mm front rotors, the 345×24mm rears, and Paragon's 2-piece rotors are all sold as shared-fitment products.

Suspension follows the same logic. AST and MOTON develop their Z4 G29 / A90 kits against the same geometry, with spring rates and valving spec'd for the platform's weight distribution and multi-link rear. One part number, two cars.

Why AST x MOTON Suits the Platform

The G29/A90 is a short-wheelbase, relatively light, rear-drive sports car with genuine chassis talent — and factory suspension that's been deliberately set up for broad appeal. The Supra's Adaptive Variable Suspension (AVS) and the Z4's M Adaptive dampers are capable on the road, but both are closed systems with a fixed tune, limited range, and no serviceability.

AST and MOTON flip that. Every set is built to order against a spring rate and valving spec that matches how you actually drive the car — fast road, club days, time attack, or full circuit competition. The dampers are monotube, fully rebuildable, and revalvable, so a set spec'd for street use today can be rebuilt for track use three years later without being thrown away.

The AST x MOTON Range for the Z4 G29 / A90 Supra

We source the platform in the following configurations:

• AST 5100 Competition — Inverted CO: The flagship AST single-adjust setup for the platform. Inverted strut design for lateral load handling, with camber-adjustable front top mounts and rear top mounts included. Our most popular option for fast-road and club-day Z4/A90 builds.
• AST 5200 Series (2-Way): Independent rebound and compression with remote reservoirs. For drivers who've outgrown single-adjust and want to separate corner-entry and corner-exit behaviour.
• AST 5300 Series (3-Way): Rebound, low-speed compression, and high-speed compression each on its own knob. The top of the AST range, suited to time attack and semi-pro track use.
• MOTON 1-Way Clubsport: The entry into MOTON. Non-inverted monotube, 1-way with 12-position rebound, camber-adjustable front tops. A strong step up for serious club-level track use.
• MOTON 2-Way Clubsport: Inverted, monotube, independent rebound and compression with remote reservoirs. 15-step damping adjustment.
• MOTON 3-Way Motorsport: Inverted, monotube, elevated top guide with helper piston. Independent rebound, low-speed compression, and high-speed compression. This is the damper spec running in endurance and GT programmes globally.

Which tier you pick comes down to how you drive the car. A G29 spending its life on the road with the occasional spirited drive is well-served by 5100 Competition. An A90 running regular club days or a driver coaching programme typically lands on 5200 2-way. A time-attack or endurance-spec build goes straight to MOTON.

Tuning and Setup

A set of AST or MOTON coilovers is only as good as the setup running through them. Two blogs are worth reading before you order:

• 1-Way vs 2-Way vs 3-Way Adjustable Damping Explained — what each adjustment actually controls, and how the AST 5100, 5200, and 5300 Series map onto real-world driving.
• How to Adjust AST & MOTON Coilovers — the practical guide to where the knobs are, which way to turn them, and how to develop a baseline setup on your own car.

Once you're lowered, a full four-wheel alignment is non-negotiable — ride height changes alter camber, toe, and caster. On the G29/A90, the factory adjustment range is limited enough that Suspension Secrets monoball bushes and adjustable links are strong additions for any tracked car.

Pair With Your Z4 / Supra Brake and Chassis Upgrades

The G29/A90 responds well to a coordinated upgrade path. Stiffer, better-damped suspension exposes the limits of the factory brake pad compound and the rubber-bushed control arms that weren't designed for sustained track loading.

• Brakes (stock caliper): DIXCEL Front Rotors (348×36mm), DIXCEL Rear Rotors (345×24mm), and DIXCEL pad compounds to match your driving style — see the DIXCEL compound guide.
• Brakes (2-piece rotor upgrade): Paragon 2-Piece Front Rotors (348×36mm) and Paragon 2-Piece Rear Rotors — reduced unsprung weight and better heat management for tracked cars.
• Brakes (big brake kit): Brembo Pista 355×32 Front BBK for A90 — the step-up for sustained track use.
• Chassis: Suspension Secrets monoball bushes, adjustable drop links, and camber-adjustable top mounts — the factory rubber-bushed arms flex under track loads, and the geometry range of the OEM setup is tight.
• Intake: aFe Track Series Carbon Fibre Intake for the B58 — shared fitment across Z4 and A90.

Frequently Asked Questions

Are the Z4 G29 and GR Supra A90 really the same car?

Under the skin, effectively yes — same platform, same suspension geometry, same B58 engine, same brake fitments. The styling, interior, and damper tuning differ, and final assembly happens in different countries (Germany for the Z4, Austria for the Supra), but from a suspension and brake hardware perspective they're treated as one platform. That's why our AST x MOTON kits, and most of our DIXCEL and Paragon brake products, cover both cars with a single part number.

Which AST or MOTON series is right for my Z4 / Supra?

For a street-primary car with occasional track days, AST 5100 Competition is the benchmark. For a dual-purpose car running regular club days, AST 5200 2-way is where most serious builds land. For time attack, endurance, or a dedicated track car, MOTON 2-way or 3-way is the correct spec. The 1/2/3-way blog walks through this in detail.

Do I lose factory AVS / M Adaptive damping when I fit coilovers?

Yes — full coilovers replace the factory dampers entirely, so the adaptive system is no longer in the loop. That's not a downside for most buyers; the AST and MOTON range gives you a much broader tuning bandwidth than the factory closed-loop system ever offered, and the dampers are revalvable, so you can retune the car instead of replacing it.

Are AST and MOTON coilovers rebuildable?

Yes. Every AST and MOTON damper is fully serviceable. Seals can be replaced, oil refreshed, and the internal valving respec'd for a new spring rate, aero package, or shift from street to competition use. A well-maintained set lasts decades rather than being a consumable.

What's the lead time?

AST and MOTON are built to order at the Dutch facility. Typical lead time is around four weeks for the standard AST range; MOTON and custom-spec AST builds can run longer. If you need it faster for a specific event, talk to us before you order — we can sometimes expedite a build, and occasionally there's stock available.

Do I need to order camber plates separately?

AST 5100 Competition, 5200, 5300, and the MOTON range for G29/A90 ship with camber-adjustable front top mounts as standard. Suspension Secrets top mounts are a separate upgrade if you want additional caster adjustment beyond what the coilover mounts provide — useful on dedicated track cars.

Do I need a wheel alignment after fitting?

Yes, always. Any ride-height change alters camber, toe, and caster — so a full four-wheel alignment is essential after installation. If you're lowering significantly or running the car on track, pair the alignment with Suspension Secrets adjustable arms and monoball bushes for the geometry range the OEM parts don't provide.