Just noticed a crack at the top in my rear wing. Car's a 1975 4/4 and I suspect the wing has been filled and painted more than once. So, question is, if I were to get a new wing should I go GRP or alloy? Currently it's all steel. Anybody have a rough idea of cost to supply,paint and fit a rear wing? Obviously will speak to my local dealer about it. Just noticed they do Duck tape in British racing green-wonder how that repair would go...