Hi Marcus,
I have a KVA and fitted aircon 2 years ago. I really don't know why I didn't fit it years earlier, I have arrived at Le Mans very red and heat-distressed in the past. I use the Car Builders Solutions #AIRCON3 aircon+heater unit mounted under the dash on the passenger side. I removed the original heater/demister box as this is no longer required. There are 4 circular outlets, I sent 2 to the demister, and 2 to the eyeballs. I also fitted y-adapters to blow some cold air on my feet. This is a complete kit less the following items which I have added:
1. Wiring- I designed my own wiring diag, I can send you a pdf when you get to that stage.
2. Engine-driven compressor, mounted to the left side next to the oil filter, with its own belt from the crankshaft pulley. If you have a toothed accessory belt you could drive it off this, but I've not tried it.
3. Condensing radiator, as big as I could get it, in front of the main radiator. Fans x2, as big as possible, behind the radiator.
4. Pipes and hoses, custom, I went to an aircon fitter and he made the pipes and gassed up the system.
5. I got someone else to install/fabricate all the mechanical items of the system, I did all the electrics and testing.
Advantages- nice and cold of course, but also it works as a fantastic demister in all weathers.
Disadvantages- for a road car, none. For a race car, weight, and when in use a power loss. It is not climate control, you either have aircon, heating, or just forced airflow.
Everything bought new, no problems. The cold output is set to +4 degrees, so the fan speed is used to regulate just how cold you want to be. You will need fan speed 3 cruising around Le Mans in 34 degrees. As a heater, it works well.
Don't forget to plumb-in the condensation drains, there are 2.
Cheers, Tony.