Amer,

All THX Select guarantees you in a receiver is Re-EQ capability (which is a good thing) and a a fixed 80Hz crossover for bass redirection to the sub (which is a bad thing if you use towers or microsatellites). There are some dirt-cheap THX Select receivers out there, and I've heard a Kenwood that sounded terrible. Almost all of the performance, power and distortion standards relate to THX Ultra/Ultra2.