I am no racer by any means, but I would approach this differently.
Racecars need to be as simple as possible (KISS). And with endurance racing thermal management seems very important indeed.
Make the head flow. and keep it under 7000RPM. no fancy pistons needed. Get the engine up to 225-250 hp NA and THEN ad a turbo. run it at 5 psi. No intercooler needed. A intercooler is just another part to fail. Just think of all the connections in the piping.
This should get you into the 300-350HP range easy.
No expensive pistons, no electric fan (just the mechanical one), no intercooler with a bunch of silicone connectors.
This also keeps the weight penalty for adding a turbo down.
Maybe I am a crazy but keeping it simple seems like a good idea.