i have the ATR SS dual 2 1/2 and it sounds good but above 4k or so it's kinda raspy with the pit bulls, but i just put some DynoMax SS Ultra Flows(round style) on and it doesn't have that common (drone) and it's not as loud at all rpm ranges. i like it, it gives it that sleeper sound.hehe and if you get a ATR system, don't get the aluminized ones, mine rusted out after 5 years, the stainless will last forever. HTH