This revision is all flex changes that gained .2 per lap on 9 second lap track. Long story short, the flex changes in the setup really added mid corner steering after the car levels out.

Round up of the differences from a "book setup" for black carpet:
Aluminum chassis: Lowers center of gravity primarily, less grip roll potential.
Droop: I almost always run 1.5mm front, 2.0mm rear droop over ride height on all cars on black carpet.
Front springs: xray progressives aren't faster, but are easier to drive.
Front arm mounts: 1.5mm lowers front RC for more mid corner steering on small tracks.
Front upper wishbone washers: 0mm on bulkhead and 4mm on knuckle w/ SAK-C138C for steering (+camber gain.)
Rear upper wishbone washers: 1.5mm on bulkhead for more rotation (+roll -camber gain.)
Rear Sway Bar: 1.2 for more steering and rotation in general everywhere
ARS washers: 2mm for static / no toe gain.
Flex Changes: front flex added for more corner entry and mid corner steering, see below.
Bumper bulkhead screws removed.
Front motor mount 2 screws removed from chassis.
Front motor mount 1 special screw removed from one piece upper deck.
Front twist bar removed and nuts used to hold shock towers.

This setup is for USGT. I suspect less steering is needed for TC tires, but for USGT tires, this is where I landed. The car is "on edge" for my traction level at my home track, which is medium high grip technical and tight. It is not loose, but will be on a lower grip track for sure. When I travel to a lower grip track I always have to de-tune.

Detuning recommendations for more rear grip:
1) Add grip by removing rear upper wishbon blukhead ballstud washers
2) Go to a 1.1 sway bar.

Detuning recommendations for less front grip:
1) Go to -1.5 to -1 camber
2) Remove response / corner entry by adding front upper wishbone bulkhead washers and or removing upper knuckle washers.
3) Lay shock down or go to softer front spring

Suggestion to NOT change the 1.5 arm mount or flex. This primarily affects low speed mid corner. Try EPA/DR/steering angle first for those. I really like the balance/profile of corner entry and mid corner steering with 1.5 and flex. Feels right.