I have one of the original Variax guitars (500) and I put a GK3 on it. Use it with a Roland GR-33. Just have to be careful about distance between strings and gk3 pup. The Roland allows for some tweaking if the distance isn't just right; note SOME tweaking. I've been thinking about getting a Standard and adding a gk3; just haven't had the guts to pull the trigger on that decision. The 500 doesn't have pickups so the installation was easier than I imagine would be with the Standard with pickups. I might let the dealer tech do the gk3 install along with the setup on the Standard next time around.