my hatch is rusty. Fiberglass replacement OK?

Fiberglass warp????? i know metal can warp with heat, but fiberglass? whats it going to do......rust. anwyays, i wouldnt have a problem with fiberglass, thats what im going to do, with the lexan glass.
 
Get the fiberglass with hinges (not the crappy liftoff hatch) and install a lexan window. Featherweight. You can get a sheet of lexan at home depot for $70, cut it with a dremel and use window urethane to mount it.