Acutally Martin told me that the a/c would eat up the idle, so it would be a good idea to raise the idle a few notches, possibly around 1k. You wont really eat up any gas and when you start the a/c it'll idle right were it should. I wouldnt see why the stock radiator and shroud wouldnt work with a/c, as thats how they come equipped from the factory, but you have to also factor in the type of heat where in. I would run it but keep a close eye on the temp gauge.

If you are running a SR a/c compressor I beleive these units dont as cold as the KA unit do because they are also fitted from the factory as a R12 compressor and we use R134 which isnt as cold as R12. Not 100% sure, but I had a discussion with TampaLinc(Lincoln)about this and he was saying how much colder a friend of his SR powered 240 with KA compressor was compared to his. Considering he took all the correct steps in installing the system with new dryer, tube, proper evac and fill.

You might also want to consider that your not moving as much air as dual fans would move, so that might also play a role.