Cars without a functional EGR can have 3 things.
1.) Check engine light on, reduced performance since the computer runs in limp mode.
2.) Reduced gas mileage and higher emissions.
3.) Some cars will ping in cruse even with 93 octane gas. This one is a roll of the dice, you can't tell if it will ping until you do it.
You have two choices:
1.) Connect all the EGR wiring and plumbing and fool the computer into thinking it is a minor problem like insufficient flow (trouble code 33). No check engine light and no performance problems other than the possibility of it pinging in cruse.
2.) Best option is a custom tune/custom chip to disable the EGR function in the computer. This can be expensive since there is dyno time and a chip to be burned and installed.