Originally Posted by
C612DNM
The reason you need it (which people haven't answered) is to do with fuel supply/pressure. The injection system is a high pressure high flow system, a sniff of air and it'll lose pressure big time, and your engine will die momentarily. So, to combat this, the injection type tanks have a kind of a swirl-pot setup inside the tank to "capture" fuel and retain enough to keep the pump fed during low tank level cornering. Any of the later MPi tanks from a salon will do. The later pumps (MK3 astra etc) are better/more reliable than the older MK1/2 Astra/Manta etc pumps, though you could use any Bosch/Walbro/Lucas in-line EFI pump that will sustain 60-90psi.