I rang up to get a quote on getting a verso tune done on my car (should be in July), that aside, I was advised I should upgrade my fuel pump from the standard fuel pump (my car for those who dont know is a my02 wrx) to something better...

Firstly, is it really necessary, or are they trying to sell me something i dont need.
Secondly, if I should upgrade the fuel pump, can someone please:
A - Recommend a good fuel pump and roughly what it cost to buy
B - Some please give me a run through on how to change the fuel pump over.

They want to charge me $300 for a walbro fuel pump fitted, but from what I understand, I can save a decent amount of money by just buying the pump and fitting it myself.