I had the same dilemma as the original pump had done 19k miles so I changed it over the winter just for peace of mind.
The Walbro pump is a lot louder than the original one on ignition on and priming the fuel system but I can’t hear it for the rest of the din after firing it up.
Likewise mine had done 25,000 so I changed it for a Walbro as a precaution. It is definetly possible to do it at the road side, I changed the complete fuel pump assembly on a M3W that had only covered 1,000 miles in a French carpark.
