I am about to spend a bunch of money changing out all my lubrication fluids to "Royal Purple" brand and just wondering if anybody has used it in there rig ?? I have heard great things about how much it reduces friction, and some people even say that it helps with MPG. It is gonna cost about $200.00 bucks to switch out ALL lubrication fluids, but if it will add a long term mechanical benefit i think its worth it. My buddy says to use Amsoil....but i don't know much about either product.