All car's have intakes

Well, all internal combustion engines

When they wind tunnel test cars they are made with a particular airflow in mind for aerodynamics. It manages the air, over the car, though the radiator for cooling, into the intake above the radiator. There are even around little flaps in front of each tire divert and eliminate the high pressure that can build up in front of the tire. Helps with MPG's. So cutting a hole in the hood will force air under the hood increasing the pressure where it most likely should be a negative pressure. This could reduce the amount of air flow through the radiator and negatively effect the cooling. I know the WRX has a hood scoop for the inter-cooler but the rest of the car was designed around it. Having said all that It's your car and you should do whatever makes you happy. Will putting a hood scoop on the car be extremely bad for it? Probably not but it may have some unintended consequences.