my fuel pump has just **** itself in my 97 magna sedan. Is it best to stick with the genuine article as a replacement or can I go for an aftermarket one? And how hard are they to fit?

Genuine fuel pump is a Denso, reasonably reliable. They normally last a long time too, you must have had some bad luck.

Not too hard to replace, you just need to get the sender/pump assembly out, undo the two clips that hold the hose on to the pump, undo the screw that holds the pump to the rubber + pickup screen assembly - pretty straightforward, its about 1 hours messing around first time (I fitted a walbro to mine a couple of months back).

If you need a good working one, I have one on my bench at work in front of me :)