We have an all new screw-in type rear wing mount on the 22 4.0, and I wanted to share a little detail about how the adjustable wing angle works. It is very similar to the 22 3.0, but mostly just with a slight change of the angle options.
The mounting pads on the wing stay are designed with 2 degrees of rake from the start, so if you mount the wing without the wedged shim, your wing will have 2 degrees of rake. You'll simply add the mounting washer above the wing and you're all set. The kit does include a shim that is wedged by 4 degs with markings on both sides, 4 deg on one side and 0 deg on the other. If you run the fat side of the wedge forward directly on top of the mounting pad of the wing stay, you'll effectively have 0 degrees of rake with your wing. If you reverse the shim, and run the fat end to the rear, you'll have 4 degree of rake on the wing. Regardless of which setting you're running (0,2,4), you will still run the mounting washer on top.
0 degree - Fat edge of wedge shim forward, shim under the wing
2 degree - No shim used
4 degree - Fat edge of wedge shim rearward, shim under the wing
More wing angle will increase rear grip throughout all turns, but especially at high speed. It will also increase drag (reduce straight line speeds), which may affect spec racers a little, although not likely too much. I have been personally running 2 degrees myself in most cases on my 2wd buggies, and 0 usually on 4wd as a good starting point.
Have fun building your 4.0s!