Recharging air conditioning....

There should be a sticker on the radiator support or somewhere under the hood that says what it should be. I suspect it's R12.

VW retrofit kits usually consist of little more than a new receiver-drier. Conversion should be affordable. System works quite well with R134a.

1993 model year r134 was required. Your 92 originally had r12 but most everything on the system is ready for r134. On my son's 92 the expansion valve malfuntioned and w had to open the system. The new valve cme stamped with "calibrated for r134" on it. The system has worked well for going on 4 years now. We didn't replace the dryer, it's hard to get to, but if your paying someone have them replace it so they have no excuse when it dosn't work.

Note: A/Cs don't use Freon. If you are low there is a leak and that leak should be fixed before trying to recharge it.

Having said that, very small leaks (like over 12 years) are not all that uncommon and if it took 12 years to get low, recharging it may not be a bad idea, but a leak test should be done first (using a snuffer) to make sure it did not just developed a real leak.

Not really; you only have to take the nose off so you can reach the dryer. Only main things is, for the love of the Supreme Dalek, do make sure you have a wrench on the square block on the condensor side when loosing the nut. Otherwise, you may end up with bent condensor pipes. Don't ask me how I know... =(

The nose?