Pay close attention since it could be detonation or spark knock. A quick way to test that is to up the octane and listen for it.
I think it's entirely possible that the exhaust is raspy. IMO, any small displacement engine (and a 3.0 v6 is relatively small) will sound raspy once it gets into the higher rpm's. Four-bangers are the worst, but I've heard v6's do it to. I come from the SHO world, and the 3.0 Yamaha engine was raspy right about the time the secodaries kicked in. Both of my cars did it. The trick to helping to reduce it was to replace the resonator with a different type. The stock resonators were just a slightly larger section of pipe with some perforated metal inside. Replacing it with a fiberglass packed muffler helped quite a bit. It also lowered the tone of the exhaust.Sounds to me like hes talken bout the exhuast sounds.[/b]