I did make a mistake when building my machine to not account for a bigger spindle, but who doesn't make mistakes on there first build lol?

The idea of this build was just to get me going and learn from it so that when i wanted to make a bigger and better machine i would have a better understanding of machine building. However since my circumstances have now changed considerably (ie 2 kids and changing jobs) the likely-hood of me building a second machine is pretty slim.

with regards to spindles, are the air cooled ones really much worse than the water cooled? because i'm under the impression that the water cooled system requires a separate water tank and pump? which would just put the price up further.