Just in note in case someone else encounters this. It took a long time, expense and aggravation before the root cause was located.

If you run across a situation where the cross over pipes in the fuel tank are blowing off after the replacement of the Primary Fuel pump, take a good look at the wiring harness with runs from the rear control box (behind trim panel on right side of trunk) to the fuel tank area. Any tension put on the harness (such as the pulling which comes when removing the plugs from the fuel pumps) can cause the wire wraps on the harness to cut the metal RF installation through to the actual wiring within the harness. This can cause an intermittent short which makes the secondary fuel pump run at random times when there is no demand, over pressurizing the cross over pipes. The causes them to pop off their fittings or blow open, which causes all pressure generated by the primary pump to divert back into the tank. The car will stop running almost instantly as the fuel pressure drops to zero.

This issue applies only the R as its fuel pump arrangement (with a high pressure pump on both sides of the tank) is different than non-supercharged S-types.