Its doable, just make sure you siphon lots of gas out of the tank (those things are HEAVY). Go grab a haynes/chilton, it'll practically draw what you need to do to drop the tank and get the pump out.
If you think about it, its probably a two-three hour job, 70 an hour ($210), plus a $400 pump (mechanics like to use expensive stuff, helps their rep). That's about $650 after all the little pieces are put together, and yeah, you're in that neighborhood.
BUT check the relays/connecters/wiring/etc before you sink that kinda money into the pump.