we have been running 540 for novice and pro, 21.5t no boost for Vintage touring cars, 21.5t boosted, 13.5t boosted and mod
i have just received a 3rd car to try the "Ultra Sportsman V3.0 Brushless Motor - 21.5R" on blinky mode to see if it's a even pace to replace the 540 motor at club level