it's gonna be hard to make it look nice in your garage- but doable - first things first - take intake completely off (upper and lower if you feel necessary) and clean the crap out of it with a degreaser like Hi Solve, or any prepaint surface cleaner - make sure there is NOOOO polish or residue or oil left on there - scuff it up really good witha RED scotch pad - shoot it with a decent primer - they make good primers that come in cans also, don't buy the cheapest can there, get a high heat primer if possible, just to be safe - now let that dry over night, the next day, sand the **** out of it w/ 400 grit wet paper, or 320 grit dry paper, (tape off the intake holes on the bottom so no sand or sand slop gets in there) now when you are done, use that surface prep again to clean it, and do NOT touch it w/ your fingers, cuz the oils on your skin will either show up, or keep the paint from sticking - NOW - choose your method to paint - you can base coat clear coat it, or single stage it, or just spray can it w/ black, silver, whatever, than spray can clear it, but you'll never get it to look right w/ clear unless you reallly know how to use those cans, or you use a shop paint gun w/ shop expensive clear - reminder- this clear will probably die back within a couple weeks, and you may need to sand n buff it, but good luck my friend!!!
