when i got my crossfire, the spoiler had many bubbles.
this is what worked for me:
1- i sanded it and sprayed mul-tie adhesion promoter & tie-coat #1033-C from transtar autobody technologies.
2-filled the surface with evercoat spot-lite 800445 (you have to mix it with a hardener that comes with it).
3-sanded it;
4-then primer gray4603-C from transtar.
5-sanded, then used color match;
6- then jammin clear 6213C from transtar.
>>>about the color match: i am in canada, and got mine from www.robertspaincare.com. but if from the states, as there are restrictions about shipping flammable substances, i cant provide advice on it.
about rust, i have heard that por 15 works great. thats what i will use whenever i face rust. its a matter of sanding the area and then applying it before you do all of the above.
let us know how it worked for you.
i hope this helps.