Some do remove EGR assy.

DI/CRD _ Not sure if has to be electrically connected or not though_try it as stated @0-TJ-0 .
DI can be physically blocked_no fault code.

CRD may give fault code_need scan tool to clear. The MIL illumination wont hurt anything just annoying. The ECU can learn and ongoing fault codes may not re appear. Can turn off with ECU remap.
For CRD there is a in_series resistor mod (pink wire at MAF sensor) that I understand tricks the ECU, but may still need to have it electrically connected.