Yea, the 2.5 ---- i think there's an actual conversion kit available now
2 of our master techs are really into this kind of stuff. One of the guys has an old bug eye WRX with an STI motor in it. The HP to the wheels in that thing is off the charts crazy.
The one I really like is this one ---- one of our best body shop techs built this for his son to take to college. Totally cool.