its all good, before I got my car I learned all my info from allpar, to this point they havent guided me wrong, the challenger link is here
http://www.allpar.com/cars/dodge/challenger.html
Im kicking myself right not though, this info has been since before I ordered my car, I should have ordered the 20 inch rims, and used the aftermarket 18s that I have right now. That would have left me with the same car, but a killer gear ratio.