Anybody do before and after dynos? Probably doesn't make much if any difference, but my only *tiny* concern is that nifty sound is coming from the fact you're diverting some exhaust gases down a different length of tube and mixing them back in, creating a more complex waveform. It might interfere ever so slightly with scavenging.
As for the mod and the sound, I'm a little indifferent. It's something a little distinguishing and to talk about which is always nice.