best sandpaper?

according to every tech manual, yes you need to clean it first.....but honestly I woundnt bother. You need to put the adhesion promoter on before any primer. It should be first before any undercoats.

if it has had any silicone based stuff put on it(armor all etc) i would clean the SHIT out of it, cuz sanding it might just drive it more into the dash.

yup yup

I did a how to on the S-10 forum a while back, it's in the interior section, check it out... i'm mopar978 over there.