If you remove the EGR valve, your motor will ping under load unless you like running higher octane fuel. It really won't affect mileage or smoke because EGR is used to lower Oxides of Nitrogen NOx emissions that are invisible unless you live in Cali then you will notice that cloud all the time called smog
Removing is a waste because a properly functioning EGR gets turned off at higher throttle openings and engine load anyway so why bother?
Also, if your rig has a temp. sensor EGRT at the EGR valve, the computer will know that the EGR is working and throw a check engine light.
