I am thinking of going with this kit myself. I put a original A6 compressor with 134a instead of r12. I used old evaporator and condenser, just flushed both with cleaner. The system worked well, the only problem was blower motor does not push out air like modern cars do. The plastic vents in TA duct work are not sealed the best either. I had to keep blower motor on high(modern car fan motor would be on 2 or 3) for hot days and this would tax the alternator at idle. I guess it depends where you live but 134a refrigerant worked great for me until the front seal blew(which is real common on A6 compressors)
, just like 77 Canamman said. Plus when the A6 front compressor seal blows it slings oil on the underside of your hood. Don't worry about adding the newer compressor to your TA' it is lighter and takes less HP to run. The kit is a bolt on and you are not modifying anything on firewall or engine. If you ever need to sell car and that person wants original compressor and ac lines then they can do that. The 134a is cheaper then the r12 especially if you need to do repairs on AC system down the road.