Decal or paint
Use One Shot Lead Based Enamel.
THAT will stick.
Everything else is going ot peel off unless if you paint with spray enamel.
Has to be enamel because the sticker has no "tooth" and other paint will eventually come off...IF it sticks at all in the first place.
I'm curious, what is it about the car decal you like if you're about to obscure the very design on that logo/decal?
Must be the shape hey?
It just seems a bit odd to want to paint over it...unless you're talking about MODIFYING the design ON the label itself...still--use One Shot Lead Based Enamel--beware: it is toxic as hell so open a window.
It dries shiny and the colors are bright..google search it online..you can get this looking in art store, buy online or look for sign-painting paint...that is great outdoor all purpose sign paint. Sticks to pretty much anything.
Clean with solvent.