I still need to use egr valve or I will burn up piston and rings
gm ecms usually add some timing advance when the EGR is active. this is to make up for the loss of power from pumping non-combustible gas into the combustion chamber, and if done properly, you don't lose or gain any power from having the EGR active.

you just need to tune that timing out, or tune out the EGR entirely so the ECM never tries to actuate it.

there's no way you're going to burn holes in a piston, though.

engines with more cam overlap can have their own EGR effect in cruising range too, exhaust and intake gasses mix naturally in the manifold, at which point having the EGR is kinda dumb