I have the same idea.
I have the Mac mini 2014 8gb 2.6ghz with the 1tb HDD.
It is possible to add the PCIe . Do you want to run it as FUSION or duel drives?
Fusion will require basic terminal knowledge which really is easy if that's what you want. Video link here http://youtu.be/w4NqbGEJpN4
I want to run duel drive tho. So in future I can take out the HDD and add a SSD if needed.
Problem is I can't find a video to show how to migrate from HDD to PCIe.
What you need to buy
1- You might find the flex cable from someone selling Mac mini parts on eBay. Otherwise looks for 076-00040 which is the HDD Carrier which comes with the flex cable and hole to fix the PCIe down.
2 - look for an apple Samsung PCIe for 2013 onwards MacBooks. Or part MZ-JPV5120 ( for the 512gb otherwise just replace the 512 with 128 or 256 for smaller SSD or you could hunt for the 1tb version)
3 - http://youtu.be/G3MmzNRIkJM this shows how to do the upgrade. It says fusion but it's duel and incomplete because he still runs the OS on the HDD and not the PCIe.
My guess is to run the PCIe as the startup disk you need to purchase a external enclosure from OWC then use a clone software and move to the PCIe and then do the upgrade. But I would much rather iFix to release a video and enclosure for this.
I hope this help. Once I have figured it out and do it myself I will post a video.
Thanks for the follow up and inputs.
so i decided to go full SSD. i have the New SSD carrier with flex cable + 512GB PCIe + 2TB SSD i also have the ifix pro kit.
I created a time machine back up yesterday and currently creating a OSX boot drive in case. now all i need to do is find some quite time and space and then i can start the procedure. hopefully i can complete this in the next 2 weeks.
I have used the cloning software in the past on PC which was great but i think i will either just rebuild from a clean install or just restore from the time machine.
ill try share results ASAP.
I completed the upgrade today. I didn't make the video as promised but I have taken a few photos that I can share if needed.
The normal HDD mini doesn't need the whole carrier replacement as it has the fixing hole for the blade SSD already. You just need to find the flex cable and then secure it to the carrier already in your mini.
The PCIe interface is on the logic board next to the IR connector.
I did run into a little problem with the fresh install of El Capitan. Took a round 9 mins for 1 part then reboot. But then seems to stall on the "about a second remaining" for around 10 mins. But it then does reboot. I did connect it to the Internet during that time so maybe that fixed the stall issue. Not sure if there is a log file I can share to show you.
Also the Samsung PCIe SSD I said above works fine. Load time with the HDD was around 60 seconds and now it's under 20 seconds. .
I now have a faster 2.5 TB mini in duel drive setup as they are both SSD so no need to fusion.
Tonight I'll back up from time machine and the. Everything is completed.
Process wasn't to hard so if you find the parts needed at a good rate then go for it Nate.
Good luck and let me know if you would like any other info