The bare minimum you need is the longer Audi subframe bolts as well as the washers. 2x WHT006844 + 4x N10785401. Parts 2 and 3 from this diagram:
https://parts.audiusa.com/a/Audi_20...T-SUSPENSION-SUSPENSION-MOUNTING/1312490.html
OE steel arms are fine, as well as the latest revision superpro arms (ALOY00018k). Not sure about whiteline. Verkline should also fit. There are no mounts/bushings required, you can re-use your existing dogbone setup or swap to an aftermarket arm. If you're using a dogbone mount insert, though, you should inspect the lower puck that comes with your subframe so you know if you'll need a different one or not.
I was able to snag mine for $150 out of a wrecked A3 with no damage, just needed some degreaser and a power wash. Good luck!