ok heres the quick and dirty on the K04 vs the gtrs
the K04 has an extreme torque spike in the low RPM's that put a real hurtin on the tranny, the GTRS will lessen the torque spike but you will gain more HP that a K04, the tranny can handle horsepower its the torque spike that kills the tranny.
look at this and you will see what i am talking about, this is a K04 PC-16 on a manual, I've been in the car and the torque spike is crazy
heres a full GT28RS dyno compare them and you will see what i'm talking about
you do loose a little bottom end with the gtrs but it gives a much more linear power curve that is easier to drive daily.
if you get a gtrs i would set the boost at about 15-18 and you should be fine, your looking at 250ish hp and about the same torque but the torque curve is much more fluid verses a quick spike.
stole the dyno's from scirocco78 and eurojuce thanks guys for posting them :lol: