Staffi...it really depends what GT30 you would use? Some should be good for alot more power than a T4 and some are around the same.

The all should more resposive than a normally set up T4 BUT there are ways and means to improve response on a T4.

My T4 is as resposive as a T38 is and Im sure Mike R's T4 was even more responsive again.

Im trying another type of T4 on my car as we speak so should have results from that very soon.