I've had the TSP catted Y, a pacesetter Y, and the custom 4" merge pacesetter y that I have now. The Tsp comes in about 5 pieces with slip fit connections, so they say its "adjustable." I say its a freakin pain in the *** because you've got lots of joints to leak, and you will never get it adjusted just the way you like it.... one change on the left requires a change on the right. If you can work on a lift then it wouldnt be bad, but on your back its a pain. Once you got it all set up, you let the car down only to notice a 2" clearance from the ground on the drivers side... but, you already tightened the U clamps so its pretty much stuck...
Pacesetter, on the other hand, is in two pieces. That means it only goes on ONE WAY. I've got pics of the clearance somewhere... Stock height, you can get a coke can under the merge, and almost under the collector. The merge is horible though. Check out my links in my sig