The only serious downer has been the barrel. You'd best replace it with a metal one. In this case, an Armorscale item. You will need to perform some minor surgery to get it to fit, but the result will be worth it. The 75mm shells are a little "clunky" but you won't see any more than the tips through the hatches one the top hull is buttoned up, so it's not worth replacing them.
Anyway, here we are: