Sorry for the delay, but here is why I think you should buy the TSX 5-6 synchro:
These are photos of the Element factory 5th gear synchro ring. Keep in mind that this synchro is built to control only one gear - 5th. You can see this in the design. It is oriented in the picture as it would be installed on the gear shaft with 5th gear at the bottom and the spacer at the top. Notice in the first picture the arrow is pointing to a line engraved around the bottom of the ring. This is for orientation, because it needs to be installed with this side towards 5th gear, and the top towards the spacer cone. The second picture (in the same orientation) shows the inner teeth. (Ignore the dog hair.) Notice that in this photo, the lower arrow is pointing to indentations on the teeth that are not present at the upper arrow. These notches help the synchro stay in 5th gear when selected. Because they are not present on the top, it may be more likely to slip out of gear. On the TSX synchro which is built for a 5th and 6th gear, these notches are on both sides.
This is why I recommend the expensive TSX 5-6 Synchronizer. It is true that some people use the factory with no problem. But I also know of several that have had issues popping out of 6th gear, and replacement of this synchro has fixed the issue. Personally, it is worth $230 to me not to risk removing the transmission twice if I didn't have too. Although I can't explain why more people don't have problems using this synchro.
Ric