Go with the OEM.
i have installed the Schnell in my previous boxster, and removed it.
it is very hard to adjust, and connects to the cable using 3 small Allen screws, so you are basicly damaging the "threaded" part of the cable (especially if your cable has the plastic thread).
i dont see any advantage using it.
for 20$ for the OEM part, you can afford yourself replacing it every 10 years.
from my experience, the weak point of this linkage,was with its attachment to the cable.