Server with only Apple SSD then add a second spinning drive?

A server version of the Mac Mini already has all the necessary cables, as well as two drives. If you're asking if you need to purchase another hard drive, the answer is no, unless you want to upgrade the HDD already there. Our dual drive kit is for non-server models, which only have one hard drive (specifically, the top one). Our kit is an alternative to purchasing a server model, because you can install any second hard drive you wish, whereas the server model from Apple comes with both drives already.