Got my tune today worst possible day being 90 degrees out, but had interesting results. First pull the air sensor maxed out and threw a cel. The intercooler has a **** ton of flow. The tuner kept saying how impressed he was with the intercooler and flow rate. Had a couple problems, first was the radiator for the IC. The radiator cap that came with it was opening when the water got hot after 10+ pulls. So they had to close off the over flow with some tubing, I'll be buying a 1.3 bar cap to fix that. Second problem is he maxed my injectors so I need 750cc's. So he turned down the boost to 15psi. Making 308hp and 338tq for now. Also the fan that was infront of the car stopped working so I was running hotter than usual.
To answer a few question. No you don't need a thermostat you just need a anti freeze mix
Ive seen people do a half size radiator then putting the IC radiator next to the smaller engine radiator. You could do that to keep your bumper beam.
My tuner loved tuning with this setup.