The problem of intercooler in this case is not only the temp of air, is this cause a "drop pressure" when operate in high flow. Because this need a bigger intercooler.
I think, your internal parts can resist more than 1 bar, the problem is the detonation or fault of fuel, its the really danger for turbo engine, ALWAYS work rich mixture in turbo engine, like 700 to 800 milivolts for gasoline and 950 milivolts to 1 volt for alcohol(etanol or metanol), is the best perfomance mixture.
The other problem is your CR, but a thicker head gasket will help you. And the next step for you make a strong C20Let, is put a better exhaust manifold, and bigger turbine, for you get in up the max power rpm, and lowering the MEP(medium efetive pressure). Because in 5.400rpm max power, is danger for high power and standard internal parts. Vernier pulleys will help too for get up the max power.
I running with my car with 1.6 bar of boost, 10,8:1 of CR(alcohol), without intercooler, and the power is amazing..really nice.. Now with my new head, i will run with around 9,7:1 of CR, and 1 bar in day, day, and 1.5 bar in boost street race case..hehehe. When increase the boost the feeling is so nice, because you feel something kick your back, is not a foot of someone, is the torque!!! hehehe
cheers and good lucky,