I wouldn't worry much about resale value. There are so many thousands of Kamakas out there I don't think it's going to matter. To the right buyer it may even increase the price. I installed Grover open geared tuners on my Kamaka soprano. It feels much better to me now. If you decide to switch out tuners, before you make the investment, keep in mind the size of the existing peg holes as well as any screw holes you may need to make on the back of the head stock. Once you've made the switch you may not be able to easily go back to what you formerly had. Also make sure if the tuners extend outward from the head stock that it'll fit in your case. With my Kamaka modification it's a tight squeeze. Luckily though, those chipboard cases are flexible. If this is a new instrument I'd see if Kamaka could install whatever you wanted.