I dont know for sure but i'll sure say what i think it might be.

The rad is black becuase black objects absorb and release heat faster than shiney objects. Shiney objects reflect heat.

With the rad thats good becuase it lets the heat of the water disperse into the atmosphere quicker.

With the intercooler i dont know, im guessing that since its air and not water moving through it, it has to be much stronger and therefore made out of something alot stronger but that doesn't mean it has to be silver .. or black, it could be pink, yeah intercoolers should be pink.

I dunno, maybe thats it, its probably not though. im not drunk.

Peace