Bodywork help
 

im not sire if this is the right section but i didnt see anywhere else it'd fit. anyways. i'm wondering if anyone who's knowledgeable about bodywork can help me out. i've started priming my S2 and a friend told me to start with 320. i'm noticing this is taking a while to get through the clearcoat. should i start with a coarser sandpaper or just stick to it? also. i'm wondering how far do i need to go down before i can spray on primer? do i just need to get rid of the clear coat? i'm going with the same color so i'd imagine i can just and it down so its roughed up again and then take a sprayer of primer to it. any help is much appreciated. thanks.

dave