Well holy moly. Easily the best mod I've done so far. It's safe tuned to about 152rwkw, it was 75 prior to the pump. It's sooo nice to drive now! I'll have to keep an eye on my speed as it will be possible to get tickets now!
Mark seems to think that my tyres are sapping about 20-30kw so he said I'm welcome to re run it with some at's for free.