I believe it will come with all required parts other than cable and M.2 drives. I am not sure on M.2 Blank also. You can  contact Dell sales to get more details on that. Below are the part number for cables required for BOSS S2 controller for PowerEdge T550 CX96J - ASSY,CBL,PCIE,BOSS,MB,TWR CX9KC - ASSY,CBL,PWR,BOSS,MB,TWR
Hello, I've previously purchased a PowerEdge T550, but opted to leave off the BOSS-S2 module at build time. Now that I've been running the system for a few months, I am working on reconfiguring how some of my drives are arranged - and plan to pass through the RAID controller and an HBA to a storage-focused VM.  It seems the cleanest way to move the hypervisor out into its own separate controller (to avoid passthrough to the VM) would be to add the BOSS-S2 module. Looking at the parts available from the support page, I found the following:  I wanted to confirm a few things here before I put in the order: Thanks a lot in advance for any help.  - Clay
PowerEdge T550 - BOSS-S2 Upgrade