2016. Re body and drive train only,
The stock suspension coupled with the additional sidewall of the 215/45R17 size tires has really settled in nicely over the years. I experience and see the advantages of the high spring rate; coupled with aggressive stability control rear braking.
Re Poster's Question:
* some additional rust-resistant materials and rust proofing. more chip and wear-resistant clear-coat and paint up front
* water proofing the rear - the factory taping hasn't been a reliable approach for this vehicle
* Move the clutch slave cylinder outside of the bell-housing. (this design element is not for a daily driver that holds down a clutch pedal)
* Also some chassis stiffeners up front and more structural regidity for the rear
From a manufacturer responsibility perspective, changes to HP may require either tweaks to braking, suspension, chassis, the engine's overall cooling or a reduction from the thirty second over-boost. So will leave well enough alone.
Outside of body and drive train,
* separate the leather heated seats from the heated mirrors (wanted the latter and not the former)
(added a bar to keep the rear shelf from collapsing, added an amp and subwoofer, some inserts for the various front and rear cup holders and trays, a GPS)
Also the typical things that occur with subsequent generations,
* blind spot and turn signal indicators in the mirrors
* Large LED display dash - no mechanical gauges
* larger screen, better audio system, electronics package, interior detail