I have actually had luck with rustoleum 2x stuff. It does stick, just do light coats because it’s a thick paint
The black was a spazstix, the gray was also rustoleum. The windows are tinted with Tamiya tint. It will chip where it’s not backed up with some goo, like ANY polycarb paint. You can see right behind the front wheel well where some gray is missing, and down below where the spaz chipped off. 2 different paints unprotected by some flex paste chipped/cracked away.
The big disadvantage is the lack of colors, such as pearly or fluorescent stuff, or the color you want may not be in store.