Is there anyway to upgrade my M37 base with adaptive cruise control?
What parts do I need to buy? ecu, meter, acc sensor?
Anyone have done that? Let's discuss

That will depend entirely on what equipment is already in the car. If it already has a Forward Emergency Braking (FEB) system, then it might just be new Radar, ADAS, ADAS2 and ABS firmware plus new steering wheel switches. If it has a Radar and ADAS but not FEB, it depends if the Engine Room Harness is generic and already has connections for FEB braking. It may or may not, so the Engine Room and possibly Main Harnesses may need to be changed. If the car doesn't already have Radar/ADAS, it's probably impossible.

The short answer is, you can't add it. You stated that you have the base model which is missing too many of the components mentioned by VStar650CL. They're integrated to work together, so it's not something you can just slap on. Not to mention that the program needed to make everything work together is not available to the general public. On top of that, you would still need to calibrate everything, and that equipment is only found at Infiniti authorized repair shops.

All correct, thanks Rogue. I'm a Nissan tech and don't have ASIST in front of me on a Sunday to be able to check his equipment.

Even if it were feasible, it would probably still be cheaper and quicker to sell your base M37 and pay the delta to buy a used one with tech package.