well, i'll save this post for 2013 when the newly released engine drops into the f30/f32. it will be a 340i and 440i, most likely. over the next few years, when the m3 rolls out, as well, the n55 will be regarded as the economic solution that was in the _35i's from 2011-2013. i doubt it will make substantial power, especially considering how most tuners will jump at the new i-6 in the m3 and 340i/440i.
if you bought a n55, i'm glad you like it and think it's a better engine than the n54. if you like the way it sounds, that's great, too.
throwing out facts about the n55 being a better motor is just plain silly, though.