The new hotness for the PR buggies is moving the shock tower to the front of gear box. While gaining stability and corner speed it does force your wing out of a balanced position.
These wing spacers will allow you to correct it to be the original depth or 4mm closer at either the high or low mounting position. Mix and match the pieces accordingly to fine tune your wing.
Add another tuning option to your PR buggy by mounting your rear shocks to the front of the gear case. These spacers will keep your wing at the original position or even a little closer.