Hey guys. First I would like to appologize for what happened about 4 months ago, this is Nate. I have had to use to search featire for this amount of time, and now see how immature I was, I'm sorry.

Anyways...
Ive had a Flowmaster 40 series since around the start April. I replaced it today with a Vortex from www.burtmanindustries.com. At start-up, they sounded about the same.
After running it, I've noticed a few things. It is much smoother than the flowmaster, the drone isnt as harsh.
It is not as loud, but the chamber is 14" and the flowmaster's is 13".
It is still plenty loud though.
It is deeper. - Inside, The flowmaster sounds like "Brahhhh." This is more a "Brooovvv." Outside, It is much deeper. I am very pleased with this purchase. Oh yea, Im running a "Y" pipe with two 18" long Flowmaster tips measuring 3.5" wide, and still have my spare tire!
Hope this helps...
VORTEX over flowmaster.