The Trannies in all Grand Prix's are the weak leak...but like somebody said, you beat on it, it will break.

Alot of guys over on LS1Tech in the LS4 section have gotten a built tranny which can run about $1,500-$1,800....well worth the money since you never have to worry about it breaking really.

Also if you get lighter wheels and don't do burnouts, it will prolong the life of the tranny. Less rotational mass on the tranny is a good thing.