Aren't flowmasters a louvered design?

The resonators in my midpipe are louvered (hey, it was FREE!,) and they suck... but that's something else entirely.

Louvered resonators are a bad idea, they hurt exhaust flow more then they help it... it may be better then a chambered exhaust, but not by much. Flowmasters are really a domestic thing anyway, and you know anything domestic is bad! (kidding! )