Sure brother. My pleasure
First off, the cooling system we've planned. We haven't made any purchases yet, but I'm inclined towards a three or four core radiator from one of the modern Toyota SUVs (possibly from an 80 / 90 / 100 series), with electric fans, ready mounted. In addition to this, I'm also inclined towards installing an oil cooler. In tandem, these should be enough to keep the moving parts cool, while the performance remains blazing hot.
As for the air-conditioning: none. The car is a roadster (i.e., all-the-time topless car), with no windows, or roof, or even side mouldings. So any attempts to cool the 'interior', or heat it for that matter, will be quite pointless. We'll be disengaging the A/C compressor, altogether. In short, no creature comforts, at all. No stereo, no heater, no A/C, no windows, no roof, no interior door handles either. Potential passengers, are thus, advised to be ready for a quite stripped-bare, unadorned, raw driving experience.
I WILL be insulating the cabin, though. To keep rattles and squeaks and heat from the engine, at bay.