My car was just painted and I removed the windshield, ground fx, mirrors, etc to have them painted separately since I changed colors.

Does anyone have suggestions for reattaching these pieces (windshield is done)?

I have heard of people applying grease or tape to the back of the gfx to reduce rubbing through the paint when they parts move around.

 

I personally would use a spray on cavity wax(maybe called something else in the usa) .The stuff in a tall can screwed directly onto an underbody/shultz gun.(It can be brushed on if you haven't got access to spraying gear).Apart from rubbing,it would stop the moisture, creeping into the very narrow gap,from sitting there and rotting the bodywork.Both my cars had previously done this as well as several other camaro's i've looked at.It seems to particulary affect the wings(sorry fenders).Hope this helps.