Originally Posted by Tine

Scott's already reported I4 Turbo is in the plan.

BMW is able to get 1/4 power increase with adding a turbo charge.
535d with 272HP was developed from initial 530d with 218HP. -> +25% HP
335i with ~ 330HP will be developed from 330i 258HP -> + ~28% HP

So, if they use 2.0L I4 175HP from 320si, the new I4 turbo could produce 220 - 225HP, or ~190HP if developed from 150HP I4.

But it sounds impossible to make just under 300HP M1/M2 from an I4 NA engine, even if it is a 2.5L. Unless it's a 2.2 - 2.5L I4 turbo developed with help oh Alpina GmbH