It depends on the car's tuning. Without EGR, the temps at low-load cruising might increase as the engine "leans out". Some engines can take this, as stock tuning is very rich (hence the smoke... too much fuel entering the combustion chambers), but if your car is properly tuned, it will run hotter.

And no, we don't test NOx. Local emissions centers test hydrocarbon emissions HCO and particulate emissions, both of which will be decreased by blocking off the EGR.