I have had ZERO problems from the tranny. No vibes as previously stated. I am not sure, but I think the tranny are different from early to late 01, same for Gt's. The later cars have tremec 3650's which is much stronger than the t45.
Only real issue I have is with wheelhop. I have 450rwhp and have snapped a axle due to wheelhop on street tires on the street. Other than that I love it.
Now, it is still a Ford, so expect the typical fit and finish and some rattles. I work for Honda so I the rattles annoy me. But thats why you put loud exhaust on a stang.
My 2001 was the biggest hunk of **** I have ever owned. I almost gave up on ford until the 03 came out. I went through 3 motors, 2 rearends, 3 pinion bearing seals, two sets of rear taillights, and a window motor. The only thing that came good out of that car was the amount of pu$$y I got when I put the top down LOL. Also, when the rear end blew out the dealer installed 4.30 gears for free since they felt bad I had so much trouble with that car. That was all in 15,000 miles too! The poor guy who has it now has been through another 2 motors as well LMAO!