Thank you Vanadiel, 5 Rhenium, and markburv, In summary: 1)The stated "Up to 2TB" comment exists because Dell only publishes based on validated configurations it sells. Well that makes sense.  Having said that, aftermarket drives of >2TB should not be an issue and will require a GPT format.  Great! 2) The 2TB SATA drive identified in the option will be 3.5" and will occupy the only standard 3.5" location available in the chassis.  I'll look into the reconfiguration suggestion by markburv. Yes. A great suggestion to leave the 3.5" cage vacant for an after marked drive of substantially larger capacity.  Again credit markburv for the thought. Nothing like good advice from experienced folks....thanks!    
G'day,  I've got a couple of questions if you have a moment.    Looking a the March 17, 2021 document "Alienware R12 Setup and Specifications" on page 17 in the Storage section one finds Table 10: Storage specifications.  Alienware Aurora R12 Setup and Specifications (dell.com) 1) For all three configurations in the table, the last column titled 'Capacity' shows the phrase "Up to 2 TB".  Is this a true restriction or can one add an aftermarket HDD with much greater capacity such as the 5 TB Seagate BaraCuda ,2.5",  (ST5000LM000)?  Or a similar larger capacity 3.5" SSD?  2) If the R12 is ordered with the storage option "1TB M.2 PCIe NVMe SSD (Boot) + 2TB 7200RPM SATA 6Gb/s (storage)"  does the 2TB SATA drive take the physical form of 2.5" or 3.5"? Thanks for your insight.  
Aurora R12, Storage Capacity Specification