I'm continuing to search for a 525 with aircon and sunroof in the uk, in fact I foolishly let one go due to a steering box issue, but I digress...

I was wondering if or when the type of gas changed on the e34's aircon system.

I've heard it referred to in different ways, eg. non-freon/R12/R134 but I'm unsure what the difference is.

The main concern is if I find a car which needs the aircon regassing (as many tend to), am i likely to require an expensive upgrade to the system to allow it to comply with modern standards?

Thanks