I run the Power Commander 5, or PCV, on my Raptor 700 along with a full dual exhaust and higher flowing intake. The difference in power is insane. The PCV will come loaded with a tune from the seller 9 times out of 10, as that is the way it is distributed. You can however tune them yourself, but I never have. On my Wolverine, I have only the HMF Fuel Optimizer, which is made by Dobeck, and only adjusts fuel trims. The PCV adjusts timing(ignition advance) and fuel. I intend to get a PCV for the wolverine eventually, but they were not available yet when I got my exhaust, so I just got the fuel controller from HMF. If you run the PCV with no modifications to the exhaust, you will likely only have marginal gains in power, but should notice a decent increase in throttle response due to a better AFR throughout the band. If coupled with a better breathing exhaust, you should notice some pretty serious power increase, especially if you are on stock tires still. I would bet a PCV with decent exhaust would see 6-8hp increase over stock at the wheels on stock tires. For anyone on the fence about ordering one, if you can afford $320, get it. You won't regret it. If nothing else you will have piece of mind knowing you are not running lean and worrying about preignition(detonation). In theory this should not be an issue, but if the tune from the factory is on the hairy edge of lean, then just running some shitty gas will get you into the red zone and you risk detonation. My 2 Cents.