I'm looking to switch from a PCIe/D-Sub-based Lynx Aurora to a Thunderbolt-based UA Apollo 16 (in part because of the free Octo satellite promotion, since I had been eyeing it anyhow).
 
However, my PC, while new, does not have a Thunderbolt port.  It has the USB-C (I think that's what it's called, not at PC now), but my understanding is that it definitely is not and cannot be used as a Thunderbolt.
 
So, it looks like I'll need a Thunderbolt port (via PCIe card).  Given the money I'm spending, and the value I place on stability above all else, I turn to my friends here for advice!
 
MOBO is a Core I7 HW-E X99A, Processor is Core i7-6850k 3.6GHz, 6 core, 15 mg cache.
 
Windows 10 Pro, SSD OS, Audio, and Sample drives, plus two older spinners from a previous machine that are largely unused.
 
Oh, and the case (since it has the ports...) is a Fractal Design Define R4 System Cabinet.
 
No idea if this is too much info or not enough.
 
It's all about stability for me; to that end, price is (almost) irrelevant.
 
Any advice would be appreciated!

You need a T-Bolt header on your board.  There are plenty of threads on T-Bolt in this forum. 

Thank you

If the motherboard doesn't specifically have a Thunderbolt header (and that header must support a Thunderbolt-3 add-in-card), then the only option is to swap out the motherboard.

Thanks, Jim, that pretty much settles it! Now I know what to find out.