Hi @PeterGill1,
The Air cooled version of the VDF spindle that you are referring to is a little less complicated, so it might be an option for you. That being said, you may want to take a look at the Makita RT0700C it makes about the same noise as the Air cooled VDF but has the low complexity of the Dewalt.
Take a look here and see the information in the thread linked… It might help you decided too:
Convince me, Dewalt 611 or 400w Quiet cut? - #40 by Travelphotog
I personally was on track to upgrade to the 800w Air Cooled VDF spindle, but I think I have changed my mind and will be going with the Makita. I too am concerned about noise levels. I have already received the Dewalt mount, and will just wrap the Makita with a shim.