Grobe, I have the 6.5 in my truck. It's fine on a tight track, tons of bottom end, not a lot of top, but you should be able to gear up a little. What speedo are you running? Little boost and turbo would wake it up, but wouldn't run a lot. Waiting for my speedo with boost/turbo to get back so I can try it. Will probably end up with the 4.5 also.

Sym, does the problem Pastaboy is having sound like what Sourdiesel ran into? You fixed it so I don't remember exactly what it was, but was the pulley on backwards?