Thanks cropwell,
I went water cooled partly because of the high ambient temperatures here (Exmouth, WA) and also the noise. My previous spindle was a Chinese clone of a Makita trimmer/router which screamed the place down as soon as it started and burnt out due to overheating. The new spindle makes as much noise as the pond pump before it starts cutting.

I was a bit surprised by what the salesmant at Auto-Pro said about anti-freeze but I know he's no idiot and thought a few other opinions would be worth getting.

Kit