We use a similar setup to your current one on our 600 autocrosser with the '07 Saturn Ecotec.The high pressure filter is from a Mazda RX7 with fuel injection. Return is back to the bottom of the tank. Abarth runs at 58 PSI. The variable speed pump would be an upgrade possibly down the road. Currently what I have for the few miles I drive it each year seems to work without issue. I issue with using the stock pump is that the Abarth OEM tank is flat and the X fuel tank is high. It would take some different engineering to allow the stock OEM pump to work correctly. When I test the engine in the test body the fuel cell I use has the stock OEM pump in it with fuel tank level sending unit.
Grimsby Ontario Canada.
The Saturn doesn't use a return at the fuel rail.
In our case we are using a Summit 3 gallon aluminum race tank with connections top and bottom. We use a Walbro/MSD? 80-100 PSI pump pulling from the bottom of the tank with a carb filter ahead of the pump. The pump outlet runs back to a bypass regulator mounted directly to the top of the tank.
The pressure line continues on to the fuel rail, no filter or gauge after the pump. It's been running for 8 autocross seasons with no problems.