billy had me recently wet sand with 600 grit over the texture stuff but have to make sure you get a good scuff. if youre paint code is same as mine then if you have him paint the parts i got few thigns needing painted as well. I went off roading with my blazer and billy painted my textured valance and it held up to the woods and abuse.
if you want it perfectly smooth youre going to have to sand alot of the texture off. but be best to let him do it ill pm you his number