ORIGINAL: CARNVR09SRT
Since it's using Mobil 1 I would do what the manual says, unless you just feel compelled to give your dealership more money. If you switch to a standard oil (non-synthetic) then do the 3000 mile oil change. As long as you are following what the manufacture recommends you are good to go. Can't help you on the kicker sound question. I've got it in my car too, but I haven't messed with it much.
Hope this helps.
Don't even think about changing over to non-synthetic oil in your SRT8. The engines were specifically designed to use it. The tolerances are really tight and dino-oil may not be able to get into the tighter spots that need lubrication and you can end up with excessive wear and premature engine failure. The Corvettes are the same way.