The guy at diggity design built me the 3mm rear tower, which I paired with the tc4 factory team shock mount(#31102) to fit the ntc3. It is a direct fit, and the mount is like $4 or less. I did have to drill two extra holes to lower the rear shocks as shown in the picture, but you can use the regular holes too with no adverse effect...
The double swaybar does give me the opportunity to run a very soft set of springs all around without too much body roll in the corners: the car feels very flat in corners, and transitions very fast....
I know I have lowered my ntc3 body so much that I had to cut the two top motor fins(12grams off), so the motor can fit under the roof....