Exactly what he says on the site. 15-25% increase in power and fuel mileage.
I sent him a Nitrostar 25 from my first Savage. It had one gallon on it and ran OK.
When I got it back it was a totally different engine. it ran so smooth.... the truck hardly even vibrated when idling.
I wish i had not dumped the pics of that engine, it was beautiful. I ran 8 gallons thru it and sold it still running like a top.