I would remove the optical drive and install hard drive caddy (data doubler), then cut out a hole in chassis to route sata power and data cables to outside. I have a dummy empty mini chassis that this 3.5 drive would hide in.
I would remove the optical drive and install hard drive caddy (data doubler), then cut out a hole in chassis to route sata power and data cables to outside. I have a dummy empty mini chassis that this 3.5 drive would hide in.
both will be limited by your network speeds, the time capsule sounds like the cleanest option and it doubles as a switch, and you can manage it remotely using airport utility.
The mac mini sounds like a complete hack-job and you should forget about it.
You won't see a difference with Time Machine performance on either. It's purely a matter of disk and network performance. Effectively all the CPU load happens at the client end.
There's a lot less configuration and work involved to use the Time Capsule for backup, so I'd just use that.