I have a 2nd hand spoiler for my Granada which is currently painted white and i'm going to paint it blue, when I rub it down would I need to prime it with plastic primer first or could I just do it with normal grey primer and then paint and lacquer?

 

I would say either - or mate to be honest. Same may say DUH of course use pastic primer on plastic. However plastic primer allows for some flex like for use on bumpers e.t.c. Spoilers are pretty rigid so wouldn't imo need a flexible primer on there. Normal should be absolutely fine.

 

I find that plastic primer adheres better, but that's out of a rattle can! Normal primer should be ok from the tin.