I'm about 90% sure there is no EGR system on I6 Zed engines. If you do find one, go ahead and block it off and see what happens. Keep us updated.
Obviously, there is benefit to not contaminating intake air with exhaust gases. However, under certain conditions, a non-functioning EGR system can increase the likelihood of pre-detonation. The anti-knock system will detect this and retard the timing. This will have a negative effect on performance, so unless you run higher octane fuel, there sometimes may be little net performance gain.