I would be perfectly happy with my airtec 100 at 500bhp, anything more than that I would work on the advice of my mapper but as air temp is critical on big power turbo cars you can bet that the £700-£800 extra cost is a wise precaution...after all a 600 bhp by is not a cheap piece of engine sitting in the car, same as you wouldn't run it on Tesco value fuel.

I know that when Mark does my alloy block stroker he will make me get the spec r and I wouldn't want to risk a £4.5 k block (£10k plus) engine on anything less than the best.

If budget restricts the the airtec 100 is one of the better coolers for reasonable budget IMO.