I just finished replacing the VSS electronic part (the $100-$130 one, not the entire $395 mechanism) on my '91 L sedan, and I must say I ran into just about every difficulty described by others in this thread. Could have probably changed out that module right there on the car, but the two phillips head machine screws underneath the dust cover had other plans.
So my other lesson learned is that my old golf tee trick to plug the hoses once I removed them didn't work and I ended up with the entire reservoir of P/S fluid on the floor under my car. Lesson learned is to simply drain the hoses into something right there once you disconnect them. Once the entire distributor-like assembly was off my car, a hand-held impact driver convinced the screws to yield to Zod.
The kit nowadays includes the o-ring, torx bolts, dust cap gasket, and plastic wire tie. Interestingly it doesn't include replacements for the phillips-head machine screws, which got a little gnarled in the process of my beating them into submission.
Being that my car is 22+ years old with over 273,000 miles, I was curious whether this was the original VSS that I removed but I simply could not tell; could see no dates/markings on the old one to indicate age, and the previous owner was an Acura Tech, so it wouldn't be surprising it would still look 100% factory after he finished with it. Shoot, even the battery in my car is a Honda battery, he was so into OEM.