1. No not reliable. Yes, bad seal that leaked oil on drive belt, replaced seal and belt and misc clutch parts. Shift ball detent, both when new. Actually parts have not been the problem, quality is the problem.
2. Have not got rid of it, no one wants it.
3. Kubota Sidekick
4. Damm near impossible, some parts are on ebay.
Mine is a MSU500 bought new from Tractor Supply.