I would vote for the T56 Magnum. I have a TKO600 behind my LS3 and only about 50 miles driven so far. I first had some issues shifting but it was a loose shifter lever that was binding. I am not past the 500 mile break in point yet but I already feel like the shifting is better. I think shifting gears is going to be fun with either but I just saying if I was to do it over I would spend the extra money and get the T56. I would also suggest you call Hurst Driveline for some more info
