really, how important is that plastic stuff?

I have a 600f4i and some of the plastic bits on the front cowl are busted so that the "COVER, R. *NH430R*" does not really attach any more. How about I just remove this upper cowl cover. Does a ratted cbr ride poorly at high speed?

aerodynamics; i would think you would get resistance and vibration at highspeeds. also they protect hoses and vital parts.

Lots of people run street fighter style sport bikes. They are not necessary, but I'd imagine the ride will be a bit more rough at higher speeds where you don't have good wind deflection.