i've seen people asking about that kit before, i'd say crap because i've never heard of anyone buying it, i don't know about you, but i don't want to e xpirament with something like a turbo kit
some may tell you AA, but i've heard a lot of bad things about them
but i've heard a lot of good things about boostlogic so here ya go
http://www.boostlogic.com/parts_bmw.html