540 for me actually
I don't see myself needing 550 kind of power, if 340 interior quality is better I might considered it, size wise g20 3 series is almost as big as E39 5 series so probably big enough me, just wish they would have better interior in 3 series.
Ps and of course i wouldn't complain if they can somehow upgrade my 540 engine to same hp as 340...