MEXICANO

My exhaust is really noisy it sounds like rocks being crushed, especially in the first 3 gears and lower RPM's, but at higher speeds they go away. I think my heat shields are the cause, but how do i get rid of the noises is my question.

Also, my radiator fans are really noisy when I turn off my car, it sounds like the fans are not lubed, but again how do i get rid of the noise ?

BTW i did a search before hand couldnt find anything and I have a 02 Z28 M6

thanks