Yes pulleys are modified, Yokomo did them for the Japan Nationals last year where duration was an issue.
They do free the car up, particularly when combined with the Bomber belts and do not alter the ratio of the car.
You can do them yourselves quite easily:
1. Using a scaplel blade carefully pry off the side that is glued on the pulley.
2. Using a fine set of side cutters cut away every other tooth.
3. Using a carbide tipped dremel bit clean up that area where you removed the teeth.
4. Glue the pulley side back on.
East Coast Bodies