Motor was completely rebuilt before the Supercharger had been put on. It has less than 4k miles on it. For what I did which is pretty much rockcrawling only I did not see the power to often because I rarely hit 5k rpm. It says at 5,000 RPM it provides a horsepower increase of approximately 35% at the rear wheels when bolted on a stock engine. Pretty easy to hookup but it depends on your experience I guess.