From one of my old posts. Everything here matches up and can be bought except, a 6in generic coolant line. VW for some reason only sells it as a kit for the entire upper rad hose assembly.
Found a coolant diagram on some Russian site that is somehow 10x better than the VWoA official parts diagrams.
Confirmed from ROW part diagrams these are the correct parts.
The right side radiator simply acts as an extension of the center radiator, with coolant flowing splitting off from the upper radiator inlet and merging back in into the coupling at the water pump
Right Side Rad - Prices for new OEM parts from
https://www.audiusaparts.com/
Air duct -
5G0117334 - 20
Water pump coupling -
5Q0-122-291-CT - 25
Lower radiator coupling -
5Q0-122-291-DS - 116, This comes with a new temp sensor hence the high price. I have found ones on eBay for 60 dollars, but I am still looking for one without the sensor
Mounting bracket -
5Q0121093FD - 65. There are several different revisions/styles of this. This is the most recent as well as the cheapest.
The actual radiator -
L&R ALUMINUM AUXILIARY RADIATOR - 150, message the seller and ask for just one, sold as two for 284.
Water hose -
5Q0-121-051-K - 20
Water hose -
5Q0-121-101-N - 27
Cross tube -
5Q0-121-070-AP - 35
Gromets for the bracket
4D0-317-867-A 2x - 12
Nut for the bracket
N90761103 - 2x - 2
Bolt for the bracket + washer
N10471802 - 2 | N90225901 like 30c lol
Washer for bolt
N90225901 - 1
Hose clamps
N-906-870-01 - 3x - 9
Hose clamps
N-906-869-02 2x -9
Generic bolt for hard-line
N90817003 - 1