S55

A platform-specific build path from stock to your power target. Mod order by stage, part recommendations, fueling and cooling requirements, and the failure points worth knowing about on that engine. Everything in one document.

The guide is emailed to you directly after checkout. PDF, yours to keep.

Submit a ticket and we will try to get back to you same day.

We’re not going to stop you. But these guides take real time to build and update, and the $25 is what keeps that going. If a friend’s on the platform, we’d rather you send them our way.

No refunds on digital purchases. Ask us anything before you buy — we don’t want you to regret it.

We update the guides as the platforms evolve. New parts come out, old advice gets outdated, sometimes a failure mode shows up that wasn’t on anyone’s radar a year ago. When that happens, we revise. If you already bought that guide, the update is free.

Guides are updated when significant new data is available for a platform. Purchase includes any future updates to the same guide.

Forums are free if your time is. The B58 megathread on BimmerPost is over a thousand posts long and contradicts itself in three places. We read all of it, cross-checked it against dyno data, and put the actual answer in one document.