964/993 engines have a provision for air conditioning, and the condenser works well.
You can use 1978-1989 AC components and replace the lines to and from the 964/993 stock compressor, but all lines should be upgraded to full barrier lines since none of the lines 1978-1989 are compatible with the latest freon available from 1989 on. The molecules of the AC charge freon are small enough to pass through the earlier hoses.
If you are running 1989-1995 engines the intake can clear the decklid condenser.
On VarioRAM engines or those with the VarioRAM intake installed, the decklid condenser cannot be used as it is tall enough to contact the condenser. Additionally, the 964 tail mechanism also contacts the VRAM so 1989-1994 Carrera2/4 cars need to change to a different tail if the Varioram is to be used. With the VRam the recommended option is to run a 964/993 AC condenser and fan in the rear of the driver’s oil cooler, opposite the oil tank. This requires new hoses, however, since new hoses are required anyway, this is not a problem, A fan can be powered from the same signal that switches on the compressor.