I run (4) mufflers. The fronts are Dynomax Super turbos. The rears are Dynomax bullets. Full 3", X-pipe exhaust. Knocks 3 to 5 dec's off and it was worth it to me.

Making 550hp, but I do like to take it out and quite often, and just needed to knock the sound down a little. It has nice smooth sound now, no drone. For cars with full exhausts, I do not believe there is any drawback. It comes down to preference. The car is still mean sounding. I have electronic cut-outs for the track.