[/FONT]apparently, there's a slight enough difference in the 15 and 16 engines that one side does not fit. I thought the 17 engine was completely different (maybe the internals are, but perhaps the case is the same). I have a 15 duke with a 16 replacement engine so I'm having a fun time trying to figure out which case savers work (also, the 16+ are cheaper for some reason, even though all years 14-17 engine cases look exactly the same on the outside)