Take baffle out, cut it down to about 5-6 inches, re-install. I did this and it gave it enough back pressure to keep it from popping on decelaration and was louder/deeper on my straight shots. Same baffle, I believe.

 

..no need to do anything to the pipes ...just wait a few months till you go deaf....sorted....lol

 

Here's a good (in general) video on the subject.

http://www.youtube.com/watch?v=KjKUKhHQLHg

 

I have V&H straight shots with the Quiet Baffles and it's still loud as hell. However, I'll second the many people's insight that the Quiet Baffles change the nature of the sound from one of being "raspy" or "tinny" to being more of a deeper sound. Almost like a "thump, thump, thump" at idle as opposed to how the stock baffles sound.

They're still gonna be loud when you get on it, but IMHO they work for what I was personally trying to accomplish...tone them down just a bit in my neighborhood (and for my ears' sake on longer highway trips) AND give me a little more torque than the stock V&H SS's gave me. I'm not nearly as technical as most of the ppl on here but it's my understanding that the Quiet Baffles being wrapped in the fiberglass creates more back pressure than the stock which then causes a better fuel to air mixture.

I could be wrong about exactly what's happening from a technical standpoint, but the end result is that I got the restored torque that I was accustomed to as well as a toned down, deeper sound.

I'm a fan of V&H SS's with Quiet Baffles.