If you've setup your valve to work well for street use, it may need to be setup differently for the track. A couple of fundamental things need to be considered. Street use needs a very fast acting valve, especially when conditions require throttle modulation, and slow throttle control. This means more vacuum to be applied to the valve. Race track use is much more of an on/off scenario, which means that the valve is NOT being asked to be super sensitive in partial throttle applications because use of the throttle is very quick.
Drag Racing - Your street configuration should do just about the same in drag racing. Unless you plan on getting in and out of the throttle quickly and frequently on a pass, it is probably best to leave it alone.
Circuit/Road Racing/Autocross - For road course applications, you will want to give the valve less vacuum and perhaps even more spring pre-load force. This means that if you're running the soft yellow spring in a DV, you might want to put the stronger spring in place. If you're running A+B to vacuum, you may want to switch to Port B only with Port A to atmosphere. What happens is under heavy braking coming of a straight, for instance, you will be generating lots of vacuum, when you start to tip into the throttle slowly coming out of the corner, the vacuum is applied to the valve, which may crack it open in partial throttle conditions where there is vacuum behind the throttle and boost before the throttle.