For what it is worth, I put a CAP 9000 Old Air unit in my personal 59 about 15 years ago. I don't know about the vent through the speaker grille, but my unit looks a lot like the CAP 4000 system. It makes cold, does not load the motor much, and seems a bit more noisy than I hoped. It is not a fresh air system, so noise is to be expected. I thought the mount brackets for the evaporator/heater unit were not durable enough so I made different ones. No complaints, but I have not worked with any other aftermarket system for comparison.
Mark
