I'm no expert on aircons, but from experience it would be difficult for the aircon bloke to blame the compressor for not dropping the temp down to 7deg - there are many other variables that can also cause poor cooling which are a lot less drastic than a new compressor, like tx valve buggered/dirty, condenser blocked etc.
The VR comp should be identical to the VS one - visually check them....however I would not use the VR one if the aircon in the VR has not been working as moisture gets inside them pretty quick when they have no gas.
A final thought and one which may save you some cash - it's very common for some aircon blokes to quote for repairs that are really not required - and from your description, and I'm only guessing that it may apply.
What happens is that the hot/cold temp dial on the console connects to a vacuum switch that turns the hot coolant flow on for when you dial HOT and off when you dial COLD. What happens is the dial operates a metal rod that connects to a flimsy piece of plastic, and over time the rod slips off the plastic so that when you dial COLD it fails to turn the heater off and your aircon then is supplying COLD and HOT air at the same time which results in warm air....exactly what you are getting.
To check if this is so, check that the brass heater pipes are cold when the temp dial is set to cold and the engine is running - they are located just to the left of the drivers ankle and up a bit - see attached pix. If they are warm/hot, then that is your problem. Simply reattach the rod so it depressed the black knob.
I lived for 15 years in Townsville and I know of quite a few blokes who've been told that they must spend a lot of $$$$ when the fix is as simple as refitting the control rod. I had a aircon bloke then who was really good and honest but unfortunately he has since left so I cannot recommend a good one, but be careful.
Good Luck.
