Performance gains are negligable on this mod, sometimes the engine will respond well sometimes they will not. The basics to it is that as it is an exhaust cam the inlet will stay open that little bit longer, this allows more air into the combustion chamber, providing a stronger mixture to expload.
The main gain of it is that the car will pick up a bit quicker and low end torque will increase slightly. It will also be very lumpy on idle as effectively you are flooding the chamber with air. Also the exhaust valves will be open when the inlet will open. Just a few things to consider. Although as i say performance gains can be alright, but sometimes the engine will not respond very well to the mod.
