hi all just wanted to ask about these 044 fuel pumps!

I have 2wd on stage 3 with the normal fuel pump would it be wise to upgrade to an 044 pump of leave it alone?
also would you trust a 2nd hand one? I been offered one for £70 with the fitting kit thats not even done 1000 miles. Im lead to think that they are bullet proof as they are used in rally cars and run duel pumps..
Any info greatfull