I think the "A/C problem" is that other's tried to use the 3.4L compressor.....which is for the newer type refrigerant. I think that resulted in leaks and not so cool A/C. The 3.0 and 3.4 compressors look almost the same on the outside. The only difference I noticed was in the valve body and the pully. The simplest thing for me was to switch the pully's and that appears to have solved the problem.

I read about one guy who switched the valve body's and another who had custom hoses made to retro-fit the newer compressor (the connectors are different on the two systems). I think this was done to try and convert to the new refrigerant.

Trying to switch to the newer refrigerant might save a little cash when recharging tte system. But, from what I hear it doesn't work all that well. My solution was to keep the older system and pay the extra cash to have it recharged.