so i just bought a si grille for my rr r18 coupe. my only problem is the grey lower portion of the grille. (yes i took off the si emblem) i am going for maybe a flat black to match the center portion of the rear hfp lip kit, and the lwer grill, fog light housing and headlight housing. should i sand before i paint? if so what grit? any particular paint brand better than the other? i was planning of picking up some duplicolor white primer, flat black color, and some clear from my local andvanced auto. should i sand afterwards? wetsand? thanks in advanced for all the help.