I put the ShoGun sliders on mine. They are pricey ($200-250) BUT they have mount bars that go from the front to the rear engine mounts so all the stresses are kept away from the frame (and no, it won't hurt the engine cases if you drop the bike.)
They do require a slight modification of the countershaft cover though. (It isn't difficult if you have some mechanical skills, a hacksaw and a file and a vice to hold the cover. Taking my time it took just over an hour total. It actually took longer to get the fairings off and the countershaft cover cut than to put it all together.