Hmm
I dont really know what type of special tool youu are talk about but its no big deal to change fuel pump on audi V8 (or 100/200, same).

*Remove the fuelpumprelay and start the engine so the pressure is realised.
*Open the trunk and remove the carpet
*Remove the three star bolts
*Disconnect the wire to the pump house
*Disconnect the hose CAUTION the fuel system can/wil still be under pressure and when you lose the hoses 30 cm from your face, big chance to get lots of fuel in your eyes, so be carefull.
*Take a good srewdriver or somethingelse that has a edge
and a hammer. Knock the metall ring carefully round so it comes
lose.
*Lift the hole house upp carefully and disconnect the return hose
(Black) with a 17 I think.
*Down with your hands in the tank and lift the first plasticring around the pump up.
*Take a srewdriver and carefully lift/bend up the inner plastic ring.
*When the inner ring is lose, the whole pump is lose.
*Caution when you lift everything up so the fuelsensor+ARM dos not get harmed at anyway.
*Change the pump and do everything backwards when you put everything together.

A tip: Watch out when you put everything together så the fuelsensor arm dont get stuck on the returnfuel hose, first it did for me and the fuelgauge show wrong. I found out the problem in the hard way, if you know what I mean.

Good luck

Time for me: 34 min last time

Audi V8 -89 100% Ethanol converted