paint primer question

I am currently in the middle of painting my 90 and have bought some new wide wheel arches#off eBay#but they are made of fibreglass, my question is what primer would you use before painting them thanks.

The same etch primer you'd use on the bodywork

Okay was unsure if there was any special stuff and that etch primer wouldn't react with it thanks for the help.

If the gel coat surface of the arches is in anyway rough/marked etc, self etch will help the paint stick but you would still need either a 2 pack primer or a high build primer of some sort as there is no depth in self etching. I,ve fitted fibreglass arches and bodykits before and had to fill some of the marks in them even before priming.