I found my 2014 a bit "revvy" too and wanted to decrease the revs at any given speed for long distance work. This would also improve the economy.
I now have a 16 tooth front (+1 on std) and a 40 tooth rear (-1 on std) This combination doesn't affect the number of links in the chain and doesn't affect the traction control or anything, ( I do think that post 2016 models need some re-mapping here )
At stock the bike did 81/82mph at 5500 revs in top, It now maintains this speed at exactly 5000 revs. Not a massive gain, but enough for me. If you use the "Gear Commander" website you can mess about with any front and rear sprocket configuration and read-off the speeds at any given revs in any given gear. I have seen 38 and 39 tooth rear sprockets advertised, so you could gear the bike even higher.