I have a Diamondback Sorrento I want to sell. It's in nice shape, but the Shimano Altus shifters are cooked. I've replaced them with a pair of friction-type thumbshifters, which work just fine. My question is this: How much will the lack of indexed shifting hurt it in the eyes of a potential buyer? I don't know a lot about MTBs but I can see how a rider might not have time to trim a friction shifter. Should I look around for some indexed shifters for it before I sell?