Not to be rude, but is this statement based on any evidence or personal experience? Lingenfelter uses these frequently on their high dollar turbo corvette builds and they aren't in the business of cutting corners.

Its a fact increasing voltage to a pump will shorten its life. Increasing voltage makes the pump spin faster, which wears the pump faster. How much is uncertain. Could only be 1% difference or could be 50% in terms of lifespan.

Boost a pumps actually make fuel pumps flow less. Injectors might move marginally more, but overall it sort of cripples the fuel system. It really is a bandaid... Read Richard's thread for the proof.

I agree with that. However, when wired with the Hobbs switch triggered at 4psi, it doesn't see the voltage boost but for a few seconds at a time, so heat buildup and wear should be only marginally more than in the stock application (at least that's how I rationalize it to myself so I don't have to swap to a higher flowing pump).

Your hobbs switch is triggering another pump entirely, no..?

No, the Hobbs switch triggers the boost a pump to up the voltage (to 17.5V) to the stock pump. Below 4psi, the pump sees 12V.

Thats weird. Is the primary circuit isolated?

You're over my head :(

I do know it's wired in line with the gray power wire going to the fuel pump from the fuse box, if that helps.

Pumps flow more at lower PSI (to a degree).. it sounds backwards and hard to wrap your head around but Richards thread explains it pretty well

The way it sounds like you've got it hooked up now, current flows backwards through the main fuel pump circuit when the Hobbs switch comes on.