I do make alumimun and fiberglass tub, for a street car fiberglass have a lot of positive side more quiet ride, less heat in the foot box,you can paint it to match the exterior put the negative side it make the heavier.The alumimun footbox it more a race look, light wheight and my vote is for the alumimun
Originals had a fibre glass spare tire tray with the rest of the trunk al. One difference I have come across is the rear wheel houses, some were al, others fibreglass. Another choice, black or wite on the footbox/trunk tray/wheelhouse fibreglass?