The M division had more experience with the N54 than the N55. I assume an N55 version could come out but who knows since a new 3 series coupe is a couple of years away.
Originally Posted by vase330
Don't you think there is a reason BMW used it in the 335is, the Z4 35is and even the 135 M? Eh ah that said, it all depends on tune level on either engine.