I live in Central Florida and my 300D was "blessed" with a proper (is there such a thing?) 134a conversion when I purchased it. Two words, it sucks. I just received my 609 certification from MACS (Moble Air Conditioning Society) to legally purchase R-12, and I am slowly getting the parts and materials together to make the system "right" again. Since at the moment, this my only car, I have to plan because it will probably take the better part of a day to reverse convert because of everything I have to do to insure a leak-free system that won't self-destruct from contamination. Listen to what everyone says and if at all possible repair your system and keep it R-12. Ok, I will shut-up now.:p