Parts Needed for EGR Service

I apologize for yet another EGR valve question, but I want to make sure I get everything I need to avoid headaches.

I have a 2015 model with 106,000 miles. This morning, I experienced the dreaded rattling for about 10 seconds when I started the car. I want to order the parts needed for my mechanic to replace the EGR system, but I'm not entirely sure which exact parts I need. I see an EGR valve part as well as an EGR cooler. Do I need both? Also, there is a vast array of pricing on these parts. Is it necessary to get the OEM parts?

Thanks so much for any help provided and I apologize for any redundant questions. I searched and couldn't find exactly what I needed.