I was a disbeliever until I drove a buddies car with them on it. I was hooked. It's not about the sound at wide open throttle for me. I can live happily without that and have only done a full throttle blast or two with them open.
I like the sound when I open them when pulling into and out of car shows and other events. The music of an uncapped big block Mopar with a big cam loping along is one of my favorite noises. It's a real crowd pleaser too. I get nothing but thumbs up, even from the cops.
The trick most people miss when they install them is to use a megaphone type exhaust tip after the cut out. I use the ovalized cone type. It sweetens the sound much like a musical instrument does. The sound with a straight cut pipe and no coned tip doesn't sound anywhere near and good.
I had a buddy who had a shop install his cutouts way back by the mufflers, and it sounded like crap. The best place to mount them is after the collector and before any crossover in the system. More importantly is add a ovalized cone after them. It makes a huge difference.
I've also had bad luck with every brand except QTP. They have been ultra reliable for my and my buddy.
