Seems like your pictures links are not working right now. And I agree, I had the same issue. And to be clear, there are a total of three C-clips (two 'external & one 'internal' type) that are used to hold this shifter together. They are:
#1 - The very large C-clip (+2") size that holds the two blue anodized aluminum pieces that make up the 'pivot block' housing [external type]
#2 - The small C-clip that retains the brass pivot ball onto the shaft of shifter arm [external type]
#3 - The middle sized (1 7/16") 'Internal type' that hold the actual white plastic 'pivot block' inside the blue aluminum housing.
The issue I had with this same (I got my from eBay) STS (Short Throw Shifter) was with was the '#3' C-clip that popped out, so the pivot block slipped out. Fortunately, the way these get installed, the pivot block will not fall completely out but rather just drops down and is trapped with in the blue aluminum housing & the actual shift linkage. So you won't be completely stranded ad not be able to shift your car at all. However it's not a good situation to be in either. The most annoying thing was a damn 'buzzing noise' not to mention what a PITA it was shifting. I had to pull up on the shifter to get the pivot block back in place so I could shift properly. I too was skeptical when I installed it as well. When I assembled it, I had a felling that the #3 C-clip was not seated properly. And of course, in due time, my reservations came true. I repaired it the first time by disassembling it and reassembling it. At the time, I didn't/couldn't source a replace #3 c-clip in time, so All I could do was 'tweak' the #3 c-clip by 'gently' opening it up so it had a slighter larger OD (to insure this time it seated itself properly in the groove). I still wasn't happy doing it this way, but I had to fix the problem.
Fast forward a few months, all is still well with the STS, and I installed the CS Stabilizer bracket. A little more time goes by an all is well, but a similar 'buzzing noise' is starting to come back. Damn. And then I notice the shifter is getting sloppy again. Again, damn. Well a week before Xmas (2006 for those who might read this post in a few years....lol) the shifter seems to have dropped almost completely out this time! Now I literally had to lift of the shifter completely if I wanted to shift the car at all. Not GOOD! Fortunately, I hooked up with 'MegaSoreAss' during this troubled time so he could show me the TWM shifter he got for Xmas (Really, he just bought it, and got his girlfriend to pay for it, you know 'as a Xmas gift' LOL). That was it! After seeing it, and fed up a second time with this knock-off STS, I ordered myself the TWN STS. Well, when I went to install the the TWM STS, The #3 c-clip was still in place, however it was quite visible that it was starting to pop out again, but more importantly, the reason the shifter 'dropped' on me was that the bolt welded to the counter-weight that attaches to the CS bracket and ultimately holding the shift linkage in place at this end), had stripped on me, and come loose. Again, not knowing this up front, I ended up (carefully) grinding away the bolt (those who have done it will know what bolt I'm talking about), replaced it with a Allen Head Cap screw, installed the TWM STS, and all is great! The shifting feels even smoother now! Oh, and it seems that the length of the section below the pivot ball on the TWM shifter is slightly longer than the B&M Style shifter, thus making shifting a little more shorter. By how much you might ask? I don't know and I won't speculate. Nor should anyone else.