Congrats on the new car :) what dis you get?
Don't think changing the wheels will void the warranty- but best consult with your dealer as they have different policies. Anything else (electrical, etc will void it for sure).
Is this the front bumper part? If so, the paint there is very thin and you'll go through it in no time. Paint cleaner or a light finishing polish by hand would be best :)
Cleaning ability of the DP Prep Polish is good, I've used it extensively both by hand and machine and actually really like the finish it leaves behind.
Sonax's Paint Cleaner works with PNS, not sure why but it does. No bonding issues so far and I have it on my daily driver.