Hi James we had a NEQ6 Pro and it was making those same noises we adjusted the gears and got rid of 98 - 99. % of the noise but that was not good enough and done the belt mod conversion .
There was no modification to the housing at all .
All up it was a good conversion and well worth the money.
We got it from Dave link below .
http://rowanastronomy.com/products.htm