Originally Posted by Levi
First: 1M has Z4 sDrive35is engine and not 335is.
335is has N54B30O0 with BMW Performance upgrade.
Z4 sDrive35is / 1M have N54B30T0 with so to say "BMW M" upgrade.
This is 100% incorrect!
The 335is has the same N54B30TO
that is used in the Z4 35is and the 1M. Here's a link to a technical specifications release from BMW that I had posted earlier showing the the 335is as having the N54B30TO variant - https://www.press.bmwgroup.com/press...hmentId=172566
The 320 HP rating of the 335is is supposedly due to a more restrictive intate on the is. But this lower rating is open for debate as it's unlikely that intake variations alone would account for 15 HP diff and early 2011 tech specs, manual etc., had the 335is listed at 335 hp. This is more than likely a marketing decision to not appear too close to the M3 numbers. The 335is dynos I've seen, the numbers are close to the 1M - anywhere from 295 RWHP to 315 RWHP, depending on the dyno conditions.