Its a major weight saving.
Remove the A/C rad and stick your oil cooler in the slot. Remove the pump, plumbing and that funny aluminium bottle, that saves a fair bit.
Drive car hard, get really hot, sweat buckets and save about another 10 kilos!
Garage Bomber hasn't any A/C. Keith Cowie hasn't. Gary Passingham hasn't. Tim didn't in the some of his. Andy Barnes probably has because he likes to appear cool....
In truth, it is a bit extreme.