I raced my XB4 at Mikes Hobby Shop last night.
I'm pretty sure it set the Track Record and Track Fast Lap (first to reach 21 laps and break into the 16 second fast lap).
I had challenges practicing with it this last week, but it came together just before racing. I put the NT1 metal diff gears in the rear and was able to set the slipper back to the manual setting. The car felt great all night.