I know for a fact that the front and back eurethane bumpers require a flexing agent in the primers and paint.But how about the fibreglass bodies on these cars? Anyone know if they require the same flexing agent?

I painted mine last year and only used the flex agent in the mixes for the bumpers (urethane single stage on 2k primer).  I could see the potential merit in using it everywhere, but went with the advice of the supplier.  So far no cracking or problems have shown up (in either the bumpers or body), but I haven't been wacking it into fences or anything.

Rigid fiberglass panels do not require flex agent in paint or primer.  Fiberglass does not flex; when you've reached what would otherwise be a flexing point, fiberglass cracks or breaks.  Flex agent in the paint or primer won't help you there. 6880Mike2008-04-03 05:29:34