I haven't bought them for the supra, but I did an EGR block-off years ago on my eclipse and I can honestly say I felt no power difference, and I had problems with part throttle knock afterwards. I hooked it back up. The EGR is closed under boost and WOT anyway. The only time it's open is part throttle cruise, and it allows the ECU to run a leaner mixture with more timing advance while still keeping combustion temps in check to prevent detonation or high EGT's.
If you're running standalone and can adjust your part throttle target AFR and fuel mileage isn't a concern for you then you don't need EGR. Otherwise leave it there.
