If you plan on racing on a track where top speed is an issue, not just on little straight away, but a track where you run wide open for a considerable distance get a vspec, it will out perform the p5 on the top end. But if you have a smaller technical track and are interested in quickness off the start and bottom end power the p5 will out perform the vspec. Don't get me wrong, both of these engines are top notch and you can't go wrong with either one. But as far as i have seen and i have driven both, the p5 has more lower power and the vspec has more top end power.