I would have thought on a 600BHP engine a certain amount of rebuild costs should be considered.

Rally teams rebuild after every rally dont they? and they are half the power.

Dont forget its a very high stage of tune.

The ultimate cosworth though, Depends if you would sacrafice the ultimate escos for the sake of 4-5k. Youre in so deep already and its not as if the cars gonna be worth peanuts afterwards, I would imagine it would get 25k in an instance.