Can't comment on the 2.2Kw water cooled spindles as although i have a few I have never looked into them.

However when Ketan at ARC was looking at the air cooled range he carries he bought about 6 which we ran and also stripped to see what the differences were.

Basically 4 of the vendors were lying thru their teeth about what was actually inside them, all the lies were about what bearings were fitted.

The two remaining vendors did have genuine high grade German bearings fitted and there was virtually no difference in their products.

I see no reason why the water cooled spindles do not follow this same pattern. Personally if i was in the market for one I'd go with Chai.