I think for the most part they are pretty much the same. I don't have any super accurate means for measuring any of the components but from what I can see, the length of the silenced plungers appears to be the same as a standard one; meaning slightly reduced travel I suppose - I'd guess maybe .3 to .4 mm? Some things you might have also noticed:
- The locking tab on the silenced plunger is not as aggressively angled, meaning it's much easier to separate it from the main switch housing.
- The locking tab can exit in two places on the silent switch, but only one on the standard switch I used for this comparison. Most Topre switches have the two exit points for the locking tab so this might be something they changed recently - or maybe it's only for the LED switches?
- There are two locking tabs on the switch housing on the silent switch compared to one for the standard. Once again I think modern Topre switches all use two. I'll admit at this point that I got lazy when I was choosing the standard Topre comparison switch. I took the 3-switch PCB out of the 9400A because it only had two screws
Anyway, yeah I agree about the pricing difference. They're basically identical to normal Topre switches but with a very thin foam ring, with a plastic coating on one side. Probably why it's a popular DIY mod.