Let me preface this - I know nothing about A/C! Also, I apologize if there's already a post about this, but I can't figure out how to use the search function on this site for the life of me.

My 87 V8 Cougar's AC doesn't work - started out as a slow leak and then turned into an issue where it wouldn't keep a charge more than a few months. It got to be a pain, and I just haven't had A/C for a few years now. I would like to get it back up and running, and I'm planning on doing a total system replacement so I don't have to worry about it again in awhile. I've run into a couple questions I was hoping someone could help me with;

I've found that you can fairly inexpensively replace all the parts of our cars' A/C with Rock Auto parts, which is where I'm currently leaning. However, I've been told that our cars are "R12", which is now hard to get with the newer systems using R134A. If I use these parts, is my system still an R12 system? Is there a way to convert the system?

I found that LMR.com has a total replacement system designed for a mustang V8 that also claims to convert it to the R134A coolant. However, I've noticed that this system's coolant return line from the compressor to the condenser runs over the engine, past the distributor cap - while mine runs to the right of the engine and then down under it. The compressor also seems to be at a different angle on the mustangs. Has anyone tried to use one of these systems in our cars, and is it worth it?

Thanks - hope I don't sound like too much of a noob!