If I had a 'intact' R12 system I would keep it that way ... But living in the southwest we still have R12 around just gave away two 10oz cans for $20 to a friend ... Heres the math the 'condenser' at the front of the car has to be bigger for R134 to do the same job as R12 is the problem ..I have no trouble finding R12 out west look there maybe ...?