What did the sway bar do for you? I'd assume it gave a lot more steering or a more free car in hard sweepers and out of corners.
The car drove flatter in the rear with it. Without it the car felt like it rolled too much on the rear end that I was waiting for it for longer than I'd like. It didn't sacrifice any grip either which was nice.

D block?
The D block refers to the rear suspension mount that sits under the rear tower.

1mm shim under that or none?
1mm shim under, none above.