Ktec Ultra system is a good price, i personally think the Milltek is over priced considering their is a 50/50 speculation over them cracking on the welds. Saying that, i like the yozzas in every way, except price, and that they are becoming really popular - no more exclusivity on those! Scorpion RS192 system is a fair price and a quiet option similar to the standard system, but i think there were issues again with the tailpipe tips not sitting to peoples expectations? I like the Piper systems, nice fit, nice appearance, great sound..
But Ktec is best on price imo.