Many run the cheapo vdo pump.
Remove the top hat from the rs4 pump and swap your top hat over to the rs4 lower assembly. When doing so swap your level sender over too. It simply unclips and you can resolder all the connections at the top hat or cut and resplice them together.
You will need to block the unused port on the pump. I used a heat gun and some pliers to melt/seal the unused line that was going there closed.
You will need to clearance the return port on the basket so your oe top hat can slide down. Once that's done bend/expand the ends of the sliders so your basket doesn't slide off the top hat.
Then swap the fuel pump fuse for a 20amp or it'll eventually blow at the most inconvenient time.