What DG glider are you talking about? I assumed you were looking for a used glider.... here appears to be only 5 non-motorglider DG-80x in the USA and I would be surprised if many of those had 15m tips. Why do you care about 15m, if you want a 18m glider buy one of those. A DG-80x would be nowhere near top of my list compared to modern 18m gliders, ASG29, JS1 or V3. What is your budget? Again if you want a 15m glider... ASW27. Lots of them around find a beautiful one.