After talking to a man I trust and respect from the G8 forums and currently a man who has a fine 5.0, I've decided to take the safe route and go with procal, filter, and GT500 axelbacks. GeorgeInNePa knows his stuff about cars, so he had a lot of influence with this decision.
My car is <3 months old and has <2,000 miles, I need more break in time and time to get any problems that may come up to come up. I will probably head this direction next year, but at this point getting a few less HP from a procal is more important than messing with the warranty.
Thanks to those who replied, but I'd rather be safe than sorry.
I'll take a chance with the MGW, lower control arms, and line lock, along with the procal, filter, and GT500 mufflers. That should hold me for a year or so.