I have just wanted to share with fellow Boss owners my exhaust upgrades from Dynomax. They wanted to use my car to prototype a new aftermarket exhaust specifically for the Boss, but found that trying to replicate the quad exhaust themselves was too costly. However, they were excited to fit their already developed exhaust built for the GT on a new Boss. At first we tried their Ultra Flo Welded series. These were just axlebacks, and a really nice sound. I would estimate the sound level on par with what already came out of the side exhaust fully open. However, you can see that 3.5" tips don't really fill that spot. Then they sent me a set of Race Bullets with 4" double walled tips along with the 3" intermediate pipe (from the H - back). This is more what I was looking for! And still not bad at cruising speeds
[youtube]http://www.youtube.com/watch?v=s1NTEPh9Slc[/youtube]
[youtube]http://www.youtube.com/watch?v=s1NTEPh9Slc[/youtube]