Removed all bolts and wires, but having trouble pulling the starter out from under the car. Any advice??
Look at the new starter, especially the mounts and see if it is possible there is still a bold somewhere that you have missed. Try knocking the starter with a block of wood and a rubber hammer. If still stuck, hook up the electrical connection and hit the starter button and see if the vibration breaks it free.
In order to remove the starter from the vehicle requires special VW/Audi tools called a Lock Carrier Tool, part number 3369. This allows the radiator support to be moved forward far enough so the starter can be removed. There are other steps involved, but without these tools don’t attempt it.
Here’s a home made version of the tools.
I also found a video on how to move the carrier forward.