F-Chassis · F91

F91 Tuning

BMW's M8 Convertible, 2020–2024. Powered by the S63B44T4 engine family.

Stage pricing for the F91

Stage 1
Tune
$495

Where every build starts. Calibration only.

Build this stage Stage 1 methodology

The F91 is the M8 Convertible — the M flagship with the roof removed. Same S63 4.4 twin-turbo V8 (617 hp Competition), same xDrive-with-rear-drive-mode, same M5-derived powertrain (full story on the F92 page). What it adds is open-air drama at the top of the range; what it trades is a little rigidity and the folding roof's weight.

It's the most indulgent way to own an M8 — a 600-plus-hp grand tourer you can take the roof off of — and it builds exactly like the coupe: an S63 with deep headroom, bought used on inspection, tuned with the supporting work any big V8 demands.

So the F91 is the open-top M flagship: M8 firepower, GT manners, sky overhead.

Parts that fit the F91

DR Forged wheels for the F91

Custom, made-to-order forged wheels — built to your car's spec, so any of them fits the F91. Pick the look; we build the fitment.

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Tech essays for the F91

Upcoming events

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Set the F91 as your garage vehicle and the rest of the store filters to what fits it.

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Before you tune.

Will my dealer flag the tune at service?

The bootmod3 flash is non-destructive and reversible. Revert to stock before a dealer appointment and the ECU is back to factory in a few minutes; re-flash after service. We document the revert step in writing so the next person opening your file knows what's there.

Is it safe for the engine?

Every tune we ship has been datalogged on the car it was written for. We look at knock counts, fuel trims, boost behavior, and intake temps before we sign off. If the numbers don't sit right, we revise. That review and the revision policy are built into what the tune costs.

How long until I have a working tune?

Most calibrations turn around in a few days. We log, review, and revise before anything ships — we would rather get it right than get it out fast.

Can I go back to stock?

Yes. bootmod3 supports a stock revert that returns the ECU to factory calibration in under five minutes. The flash is non-destructive — nothing in the BMW DME is permanently modified. Most owners revert before trade-in.