Originally Posted by Ironring Racing
And what's Mahle's sticker on there for. AFAIK, the Alpina motor is just a tuned N54, no internal work. Wasn't there some debate a while ago as to who made the N54 pistons?
The Alpina B3 / B3 S have always had low compression pistons by Mahle. Nothing new there. And that's the only real hardware difference to the standard N54 engine used in the 335i / 335iS.
The B3 S also features different primary catalysts, a secondary cats delete and a modified air intake. These - along with the flash tune - explains the difference in power compared to the standard 335i.