hey, has anybody converted to R134 (I have no idea what it's actually called, but someone who knows will get the idea)?
Do a search on Ebay for "freeze12" or "fr12". It is an R134 blend that allows you to just remove the r12 and replace it with this.
Just be sure to leave the labels and caps (note, one cap will not fit due to the way the lines work on the e30) so that no one hooks this to an R12 system to bleed it, the shop will NOT be happy. The good, it works and is cheap. The bad, you are pretty much stuck to servicing it yourself (VERY simplke and for about $50 you get the entire kit with guage, which is all you need).
But lets face the facts, it cost me around $50 for the kit, and will cost only a few bucks to recharge if it needs it, and an R12 servicing can top $200 these days.
I bought a kit with guage (about $30-$50), and since my system was basically empty, I just bled what was left (which was nothing). I hooked up th guage and freeze12, and as it started to pressurize, I bled a bit out the high pressure side to push out anything I did not want in there a second time.
Works great, I have had it in for over a year and it blows at least as cold as r12 does. The company claims it is colder than r12, and far colder than r134, even though pressures are the same as r12.