Purely subjective. Some guys love their flowmasters, others hate it and want to kill it with fire. I love my dynomax muffler setup inspired by 13secV6's summit turbo muffler catback he pieced together many years ago.
FWIW I like the sound of my exhaust made up of pacesetter headers through a stock Z28 catback minus the cat. Enough I might just keep it this way long term. My car is also cammed however. I'm not sure how it would sound with a stock engine.
1999 Camaro 3.8L A4. Cammed, so kind of fast.
2002 Trailblazer LS 4.2L 4x4. Lifted, slow.
2007.5 Silverado LT Z71 5.3L 4x4. Stock, not fast, not slow.
I think the end all be all for the 3.8 was determined to be a pieced together kit that involved Summit pre bent pipes and using Borla XR-1 mufflers. If memory serves me correctly this was a true dual set up. However if you are looking purely for a cat-back kit, the Magnaflow kit tends to sound the best on stock 3.8's. I had a Flowmaster kit on mine, but it was a 3.4 and the 3.4's sound better with the Flowmaster kit as compared to others.
Bryce | non timebo mala
Looks like I picked the wrong day to quit drinking.
I stuck a CHerry Bomb Vortex on mine after having a flowmaster and the tortex definatly sounds better imo. I ran the flowmaster both with the cat and without and it really had a ricer sound to it at higher rpm espectially with the cat off. The vortex has a naturaly deeper sound and stays that way through all rpm and it has that glasspack crackle when you let off.
True duals dumped at the axle or run underneath it are relatively cheap, but it does take some thought. If you want loud, go TSP rumbler. If you want mild and deep go Borla Pro XS or WS6 or Z28 catback. If you want loud and obnoxious go with flowmaster: clicky Cheap alternative to borla is the Summit Turbo Muffler. Hooker aerochamber was nice, until it rusted and started rattling.
2005 Acura RSX - Stock 2000 Firebird - Borla Pro XS 2.5in Catback, Magnaflow High Flow Cat , Whisper Lid, 3:42 Tuned by PCMforLess. Sold.