I was reading about N54s and 335is and came across this. What are your thoughts?

I've no intention of modifying my car but it's interesting to read about just how tuneable these powerplants are Been doing some reading on e90 post too and seeing as your only options for a 3 series in the US are 328 or 335 there's a huge amount of these cars being tuned to silly performance figures over there.

http://blog.modbargains.com/5-ways-to-full-bolt-ons-for-bmw-n54/