On a Lift from below.
I cut the back of my hands removing an almost new pump from the green machine after I totaled it.
My mechanic put it in by droping the tank. The hoses are the worst part. I cut them on the salvaged part.MoreIn theory you can replace it through the access plate in the trunk. That's how I remover the one in the green machine. It is real hard to disconnect and reconnect the hoses from above. Putting the car on jack stands and crawing under doesn't help much. With small hands and long arms it may be possible.
On 940 without the Regina pump there are two pumps one a low volume pump in the tank attached to the fuel sender monster and the other is under the driver's side of the car mounted with a fule filter on a removable plate.
The pump in the tank can be removed by popping he plate in the trunk and disconnecting the hoses and wires for the pump and sender unit. It needs to be twisted out because 1. the access plate is too small and 2. the design is unnecessarily complex. Replacement is much more difficult because the sender, tank filler assembly can come apart and drop into the tank making it necessary to start over. This is a bad design all around.
The under car pump can be removed easily by disconnection the fuel feed line and clamping it to prevent siphoning, unbolting the fuel filter banjo fitting that runs to the fuel rail on the engine, and removing the two bolts and one nut that hold the bracket to the frame. The electrical connectors are push on pull off type. The pump is a proprietary design and it can be a pain to modify an after market pump to match up to the banjo, fuel input and electrical connectors all of which are proprietary. This is another bad design.
Most problems can be solved by checking the fuel pump relay before you start.