In terms of volume: Glasspack>Super10>40 Series. In terms of sound quality and tone: 40 Series>Super10>Glasspack. I myself would say try and get a direct flow Magnaflow or Borla XR1 either one being round body to have a very nicely shaped tone with output.
Without any truck info, and no engine info, thats part of the reason why I answered, straight pipes. Sound is a relevant thing. What sounds good to me, may or may not to you. the engine, heads, cam, exhaust pipe, or pipes, a X or H pipe, cats, and type of or lack of a muffler, or mufflers will all effect the sound of the exhaust. Personally, I have a set of shorty headers, gutted cats, true duals out the back, with 2-24" old school glass packs on my 1997 Chevy with its original vortec 5.7L (350). A lot of people comment on how good the exhaust sounds. Someone posted a thread on another forum a while back of a 69 Camaro. They said they want there truck to sound like that. Well the Camaro had a big block with a big cam, aluminum heads 3 inch exhaust, and a set of long tube headers. Your stock small block will never sound like that, with a muffler swap or muffler delete.
I had a flowmaster on my Chevy S-10 vortec V6 and it sounded darn good. Don't have it anymore as the truck it self was just to small for what I needed.at the time.
I used to work with a guy who had a 2005 Chevy with a 4.8L. He pulled off the muffler, and put straight pipes. The truck gained a good bit of power, and was plenty loud. The next trick is to put turn downs just after the straight pipes.
