There are a bunch of threads on this. Do a search on Mufflers.
For the peeps running a 496, I would go with the Eddie XL Clamp ons. The will clear the swim step and get the sound down with minimal rpm loss. Plus there cheap, $150.00
I read your going with the Raylar set up. Since your putting out more ponies, I would guess the sound will get up there also. I like the Gibson power curves so far. Seem to work good with the 525 & very ltlle rpm drop. My only concern is reversion. I wish I could get a diffinitive answer on this. Are the OK or not???