OK here it is:
The lighting package would be welcome. With the LP I could probably go faster at night but I instinctively slow down a bit after I flick the headlights on after many years of experience with Halogens. The complex and expensive HID/ballast system is falling out of favor anyway, if the choice was modern LED lights all around I would be more in favor.
The bigger brakes look cool but are going to be much more expensive when time comes to service/replace the rotors. The only performance advantage for the big brakes is that they don't fade. If you are experiencing brake fade driving anywhere except the track you will not be driving much longer anyway.
The added 10hp is less than a 5% increase and not really worth mentioning unless you are driving in competition.
LSD is the big one. The Haldex-based system is electronically controlled and may require servicing at some point. It "kicks in" during cornering at speeds/g loads which should probably be avoided on public roads anyway. Still, LSD is a real driving performance enhancement in any car and it would probably help out in snow or ice as well. I would prefer one of the two excellent mechanical systems available, but they cost about $2 grand all in.
Finally, the wheels on the 2017 sport package look a bit nicer, IMHO.
There is no right or wrong answer here. My base model MT GTI hit the sweet spot for me, but it is my grocery-getter. If you are buying the GTI as your only performance car get the one you can afford and don't worry about it, you could have spent more money to get an even higher spec Golf R or maybe a BMW, or saved money with a more practical and still sporty Golf variant.
