I have true duals on a ford efi 300, headers, dual 2.25" pipes, no cats, generic bullet style turbos, exit behind each rear tire (truck).
If you go to your exhaust shop and ask for turbo mufflers they probably have two generic options, one an offset in/out pancake style and the other a bullet style, look just like the glasspacks except they are not straight through and usually painted blue. The pancake style was louder, interior wise and exterior, the bullet slightly quieter, thanks to midwest weather and rust, I was able to try both.
I can get a sound clip if anyone wants to hear it, just post your e-mail and I will send it.
The classic mustang crowd (200-250ci I-6's) seem to have success with headers, Y pipe if dual headers to 3" pipe, single in dual out flowmaster 40, dual 2.25/2.5" exhaust out the back. Especially with a performance cam, this sounds like a muffled v-8, very nice, not sure how they do it, when reved it doesn't rasp like a six normally does, IMO thats nice. I have heard a flowmaster 40 with a simillar set up on a larger ford 300 I-6 and it sounded like an I-6 with glasspacks...weird..I would think the sound would be deeper and mimic the smaller I-6 but apparently not.
