They seem to really be pushing the 'More HP gain' propoganda- with papers to back it up.. I was watching Powerblock a few weeks ago on SPIKE, and the dyno should like a 5HP gain..there website is filled with proof from other TV shows, such as trucks, ETC. and magazines that show a dyno proven power gain too. Albeit, this is over dino, but still- what is everyones opinion of RP? ..i'll be honest, i'm considering ditching the Synpower i got BOGO and trying out the royal purple for a change on the 2000 mustang i just bought with the 4.6.