The effect Aircon has on an ecu / engine is when it turns on. When you activate the aircon, it takes up load off the motor, therefor you need to wire the aircon to the ecu (just a switch), this allows the idle rpm to increase to compensate for the additional load.
All Autronics can do this, most aftermarket ECU's will have this feature. As for the VR4's climate control, it is independant from the ECU.
If you want a patch loom, KAOTIK is running one made from Springy Motors. Plug and play on VR4. This can be done for any car.
I'm running an AUTRONIC SM4. But I dont have Aircon. Great ECU's.