Help on mufflers vs glass packs

Both glasspacks and Dynomax Ultraflows are single pass designs, which IMO have the least amount of backpressure. Both work like gun silencers, although the Ultraflow has a gentle S-bend in it.

One of the problems we all face with non-OEM exhaust solutions is there is very little uniformity of enforcing noise limits. There is no federal standard. My state does not have a decibel limit, nor does it routinely equip officers with calibrated sound level measuring equipment. All the state motor vehicle code says is that the car has to have a "working" muffler on it. (FWIW: Federal EPA has noise limits on motorcycles. WTH.)

When the OP says that glasspacks are too loud, is he saying they are too loud for his preferences, or is he saying that he's been told they are too loud by neighbors or a member of the law enforcement community? The Charlotte/Mecklenburg County ordinances are about as vague and subjective as they come. http://scp09.wordpress.com/city-of-charlotte-noise-control-ordinance/ . Good luck