It seems like there's a trend for evo/wrx/sti owners to move on to 135i's lol
I had a 09wrx, cobb stage2, catless dp etc etc etc
The ease to get power from the n54/55 is something you'll enjoy getting used to.. cept the n55 parts cost quite a bit... something like 500 for a catless dp and you're looking at 500+ for any axle backs..(miss the 300$ fullcatback turboxs for my wrx)
With n54 the used market is alot bigger so you' can get some better deals
I have to disagree with the vishnu procede part.
I understand that they blew some engines? or something with the subaru community and everyone runs away when they hear shiv and vishnu.
But if you look more into e90/92 guys and people here you'll find that ALOT of us run procede and i think its safe to say that most of them are trouble free(myself included)
I haven't had the experience with jb so I cant' comment, but you'll find that alot of people prefer procede over jb.. but that's a whole other discussion
Eitherway, not sure if these random facts will help you out, but im sure you'll enjoy the switch to the 135i like the rest of us!