That sucks..

I know, it does but I cant give up. Have to keep at it.
Question: Air to Air or Water to Air?

For a circuit car I would stay with a big air 2 air.

sucks about the engine, but good on you for pressing on
can you use the boot mount cooler setup option or have you taken up the boot area with other stuff??
a massive boot mount air to air would be the go for sure..

Im not a fan of the under the boot cooler as it cops too much heat from the car. It would be mounted similar to EVO65's car if air to air.
The issue with air to air or water to air is heat saturation over a two hour stint.
Air to air is lighter efficient but could suffer heat soak. Water to air is heavier, as efficient but less heat but could suffer mechnical failure due to pumps, complex is an issue to.
Would a ebay air to air do the trick?

Not sure where evo65 has the intercooler, but i wouldnt bother with the ebay, greddy knockoffs on your car..
i had mine heatsoak on the dyno to 60 plus degrees, stationary and no intercooler fan, but still quite hot..
people have pushed 250kw on them but thats on borderline limit and lots of cool down periods between dyno runs
 
i would have thought the boot mount coolers massive fans would take care of any heatsoak and heat build up from exhaust as the fans will be blowing the heat away from the cooler..
 
worst case scenario re-route the exhaust as a side exit, and you have no exhaust heat to deal with..

Could you do a massive a2a in the boot like my old setup (Recently Surok's) with two large 12" fans blowing air through it (and onto the exhaust) The exhaust heat would only be a problem if you were stationary without the fans running.
I think the core on mine was 700mmx300mmx100mm
 
It didn't come close to heat soaking on me on the dyno but that is obviously no where near the heat of 2 hours of track time.

/\ i had your previous car in mind when i was mentioning the boot mount cooler...

I would be more concerned about the w2a heat soaking on the track. You would need a pretty big heat exchanger up front to cope with the limited off boost seen on the track.

I'm all for w2a, and even have one on my car but their not really suited for circuit racing

Thanks for the feedback people.
I had the same thoughts on the w2a where you would need 20kg of coolant system to try and manage the temps but not 100% on which way to go. Looks like I will stick with a2a but may add a cool spray system to it which I can manage from the ECU in the car. We pit after lap 70 at which stage we can refill the coolant bottle so there is no need to carry too much extra weight around. Something like a 5ltr container with a windscreen water pump to spray liquid onto the IC. The car has plenty of air flow to the IC but this will help manage it better.  
Here is a pic of EVO65,s set up. He never had a temp issue after this set up.

Also curious on fuel consumption of the 250kw+ engines. Can someone help with this?