Popular teardown site iFixit has released a kit that allows a second hard drive (or SSD) to be added to the current generation Mac Mini (mid 2011). Apple left the space available for the second drive largely for their Mac Mini Server model, which includes two 500GB drives but costs $400 more.
The kit contains everything you need to complete the job: a proprietary SATA hard drive cable, shock-absorbing mounting grommets, mounting screws, Mac Mini logic board removal tool, 26-piece bit driver kit and a spudger. While iFixit rates the job as "difficult" they do offer a detailed step-by-step guide that should help just about anyone complete a successful drive installation.
The dual drive kit is shipping soon for $69.95 and carries a six month warranty.
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