I have a 2001 Corvette C5 with an auto trans. I have 15000 miles on the car currently. I have been using moblil 1 and a napa gold filter from day 1 ( I change both at 4,000 miles) With that said I have been taking the car out more and may get into some AutoX this year ( big maybe). If nothing else I intend to have a little more fun with the car. I have heard good things about Royal Purple engine oils and was wondering if this would be a wise upgrade for my car or should I stick with M1...Whats has better protection qualities for the long hual?