Just shy of a year now with my 2016 JCW. Agree on the shifter and it is the first thing I changed. The throw seemed so long even after owning two R56's and I, for the first time in many years, found myself grinding gears occasionally because of it. Problem for me is I like the stock height due to the armrest so I really was torn. I decided as a first try to go with the NM Engineering short shift adaptor. Shortens the throw considerably and really makes a huge difference without a large expense. I have not had problems with grinding the gears once since I changed to it. Still stock height and all the same parts. I have actually decided not to change from it because I like it so much better.
Now just need new wheels and tires and an NM Power Module, but expenses on the house come first since those are necessities and these are just things I want.