I dont have my tahoe with me right now, but if I am not mistaken the exterior mirrors should be plastic? If so get you some adhesion promoter (bulldog or sem) scuff the plastic with a grey scotchbrite pad until the black looks slightly hazed then lay a decent coat of adhesion prom. to it let it flash about 5 minutes then lay your basecoat down. I would recommend you do a Basecoat/Clearcoat just because its a better sealer than just a single stage. But its totally up to you, but either way make sure you put adhesion promoter to help that paint stick to plastic, otherwise it will peel off again