Most of us LS and older DG owners have not signed the service contract. How often you you need spare parts? They can often be found from an crasched glider. There has not been any new mandatory TN for my LS1 in about 20-years, wht pay 175€/year for a paper that will never show up?

I would not spend to much time on comparing performace on gliders that are 30 years old, they perform more or less equal.
Buy a nice looking glider with instruments and trailer that suits you budget, then do what gliders are designed to do = Go flyging