The winner of the test on the medium / high and I must say hands down is the itech 8000 with a dynamic, precision, unbelievable ...;
But it really is not capable of the sub driver as he finger yet 4000 w / 4 per channel anyway.
The winner of the test on the bass is the qsc pl 380, which down the lab gruppen to be much, but down nonetheless and that is audible on both system !!!!
The qsc a rounder sound, and hard to explain but it does sound better subs in the bottom "he breaststroke finally hard to put into words."
Yet before the test I already was leaving the sight of all the fantastic reviews on the 6400 fp to push the subs that its going to be the big winner, and maybe not.
So to make a good choice in high-end amps any brand, try own system sounds with as forums reveals some truth but I have proof that the lab gruppen is not better than the qsc pl 380, and the crown is really on top of the mid / high, the other amps on mids / highs are similar, may very audible difference, share good report on the itech.