During the late 80's I fitted an old SU electric pump to my GT6 when it was first running with a 2.5L saloon engine. This was supposed to overcome what appeared to be a fuel starvation problem above 3000rpm. It did appear to cure this but in the end the real culprit turned out to be a very badly profiled fast road cam. This was supplied by a very well known specialist, so it just goes to show that crap after market parts are nothing new.
I mounted the pump on the engine bulkhead and yes it did sound like a manic woodpecker trying to escape. I had no over-pressurisation problems but in hindsight I think this was down to the fact that the pump was designed to be mounted next to the fuel tank not the engine! I reverted back to a mechanical pump when I carried out my final engine transplant in 1993, along with a properly profiled fast road cam. This served me faithfully for the next 15 years until the pump decided to shed one of it's internal pistons. This resulted in my one and only trailer home journey in 28years of ownership.
On balance the mechanical pump is probably the better route to go. Your car was designed for this for good reason and in the end despite my experience, is the more reliable set-up.
One final point about using an electric pump-it should be fitted with an inertia safety switch. This would prevent petrol being sprayed everywhere if you suffered a ruptured fuel line In an accident. I never considered this when I had one fitted but then I never had an accident.
Cheers
Alan