Well since I do this for a living Ill give you my opinion. I used mobil 1 and it was great, then I started using royal purple and it was alot better. I would not use a high mile oil b/c it is just the same as basic oil with some added not worth the money. I also agree with the penz and quacker diss. It doeshave wax in it and wll build up on your motor. I would do a motor flush, and then use mobil or royal purple. With the purple you will gain some lost hp. Might not notice at first but I say its the best. If you live in the houston area I can hook you up with some royal purple for real cheap and I also can d the motor flush for you, just let me know.