Are you running an aftermarket cat-back exhaust? Depending on what type, they might not have a resonator. Get yourself a nice straight-through Magnaflow race series resonator, and weld it in a little after the cat. It'll quiet the exhaust right up, and clear out any rasp.
BTW - Your headers are not SHO-SHOP headers. They're MSDS. SHO-SHOP just sold them.
Mark
