Fitted one on both of mine. As above, get to the rubber inlet manifold, remove it, and drill hole for spigot type thing.
Most time consuming bit was getting to the inlet manifold.
Instructions and pics are available from the scotoiler website as a download. When you register your purchase with them they will send the bit you need for the manifold.
I fitted the reservoir high up on the subframe near the fuel filler. Successfully fixing the oil feed pipe to the swingarm is a different matter which I need to revisit!