If you plan is to use only while at the track, why not take the simple approach? Just unplug and cap the vacuum line to the EGR valve. Or disconnect the electrical connector to the EGR solenoid? This will disable the EGR system and no EGR will flow.
It will throw a DTC, but since you know the cause, its no big deal. Note, EGR takes stable driving conditions to occur. The case could be made that track conditions are anything but stable. IMO, there is a very real possibility that pulling and blocking the EGR vacuum line will NOT throw a DTC because of the few number of times the PCM will even call for EGR. It is also important to note that for EGR flow related issues, the PCM does not throw a DTC right away. It looks for the condition to be chronic.
When finished at the track, re-connect and reset the code. Drive home. Simple.
When the EGR valve is closed, no exhaust gases are flowing. There is no performance difference between this and a totally blocked off EGR.
OBTW, if you install a block off plate at the TB, remember to block off the EGR tube as well. Otherwise, a lean condition will occur on bank2 as air enters the EGR tube.
