Hot Rod TV dynoed a car (about 400hp) with regular
oil (engine,tranny,diff) and then with Royal Purple and gained 22 or 27 hp at the rear tires. Also saw dyno results from a C-5 vette getting 4hp by switching to Red-Line Shock-Proof diff lube over another
synthetic lube.
I wish I could add a Tornado, Prolong, and all these other things. With all the products out there we should all be able to get about 900hp.