G15 Tuning
BMW's 840i Coupe, M850i Coupe, 2019–2026. Powered by the B58/N63TU engine family.
Stage pricing for the G15
The 8 Series is BMW's grand tourer — the car built to cross a continent in one effortless surge. That mission hides the same truth as the rest of the lineup: it's a tunable platform under the elegance. The 840i runs the B58 six (333 hp); the M850i runs the N63 4.4 twin-turbo V8 (523 hp) — the same engines doing the same things they do across the range (B58 story on the G20 page; N63 on the G11).
What the 8 adds is character, not a different rulebook. A calibration sharpens the 840i the way it sharpens any B58; the M850i's V8 wakes up with a tune and the right supporting parts, the same as the big sedans and SUVs that share it — just wrapped in the most luxurious coupe BMW makes.
The honest notes are the engine families' known items (the B58 housing gasket; the N63's maintenance appetite) and the reality that a heavy GT wants its supporting mods sized to suit. But the platform is willing — the 8 Series is proof that even the boulevardier builds.
Parts that fit the G15
DR Forged wheels for the G15
Custom, made-to-order forged wheels — built to your car's spec, so any of them fits the G15. Pick the look; we build the fitment.
Tech essays for the G15
Tuning and Your Warranty: What's Reversible, and What's Actually Detectable
The honest version of the warranty question — what Magnuson-Moss actually says, what we flash back before a dealer visit, and what...
ReadFEMTO & the Bosch DME Lock Guide for BMW & MINI
When it comes to tuning modern BMW and MINI vehicles, enthusiasts have encountered significant challenges starting with the 2020+ models. Bosch's updated…
ReadUpcoming events
Cars & Coffee Delray Beach
Cars & Coffee Miami — Jungle Island Father's Day
Supercar Sundays Florida — Father's Day Car Show
Set the G15 as your garage vehicle and the rest of the store filters to what fits it.
Set vehicleBefore 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.