ive also got a non tuned grp (but with the turbo mod) from mark and i love it (i did change to a turbo head tho) ive never felt under powered anywhere from the tightest switchbacks to the longest straights...the only advice i can give is be patient with the tuning...and make sure u have a good pipe combo to utilize everything that motor is now capable of...u might feel awkward with how lean your gonna be able to go with the needle settings (im at 2 1\4 turns from closed on the top end not at full race tune...maybe about 85-90%, but ive got a crap pipe for now) ur gona love that grp!!!