I wouldn't want to deter anyone from modifying their car, I just think that most area's have been made to suit the power on an st, and the resale would see you loose less money than on a mod'd 2ltr.
Having said all this, I always liked modifying to my own needs, and many of the aspects which the st is superior in, may not matter to you.
Do you just want to match the power, because I've seen a few posts from people who claim to be matching st170 performance from 2ltrs with pretty much pani_k's list.