I got rid of the the aircon pipes up to the firewall, both the front rad and the rad otherside of firewall, front rad to help cooling and the other one for weight, also got rid of the pulley (just to help and its obv doing nothing) and the compressor, for me it was necessary because the car is really track only,
i agree with adam re above and i dont think i would bother with this mod if you wernt going quite extreme.