aftermarket duster fuel tank

I have EFI in several cars and no problem w/ an external pump, even with mine in the engine bay. I don't have any sumps. In my C-body the pump will suck air if I brake hard with <5 gal since a wide shallow tank. Haven't driven the A's enough to say. I recently saw several external sumps on e-bay cheap ($25?). It looks like you run a low-pressure pump to keep the sump filled and it supplies the EFI pump. Some models put the pumps in the sump and some outside. You can buy the same from the high-price brands too.