I use RP in my autos (both air & water cooled.) I've never had a complaint. I've heard tales of guys opening up a motor after X amount of miles and the guts were stained purple.
I do know this, IIRC the film of RP is 800 x's stronger than the film of reg. oil.
The hardest thing ur motor does is start up.
For that split second, the only thing on the parts, is the film from when you shut it down the last time.
(thus why when my GF & I shut down our motors, we always give it a slight rev & turn it off at the same time/on the top end of the rev; it gives it a nice fresh coat of oil up into the top end.)
I've ran their other products in my other autos and have always been happy.
As I drain my newly aquired peds, I'm slowly making the switch.