Back to the original query about 16s; yes its been done. Has it been done correctly to a point I personally like it ? IMO no, not on a stock bodied X1/9. If your running huge flares, skirts and wings, then yes, 16s and 17s can be made to look good.
I'm running 15s on stock bodied X, and it was very difficult to pull the look of correctly. IMO, I missed the mark for the rear tire fitment . Im running 185/45s on 8.25 wide wheels, all around. Since at the time I was researching 15s on X1/9s, there was literally 0 results for what I was wanting to do, which is to pay homage to my Verdun roots, and slam the crap out of an X and run bigger more attractive wheels (its a recipe strait from the VW cookbook).
There was limited info out there, as most people running 15s, were using the wheels sold on vicks, which are similar specs, but Im not a fan of those wheels. I wanted something a bit more reminiscent of 70's & 80's Ferrari wheels and bought a set. I was told universally that it'll not work, and its not going to drive worth crap, and that the scrub radius, Yada Yada Yada, and the angle, Yada Yada Yada, and this blah blah blah and the that blah blah blah, of why the wheels won't work and how I've committed some blasphemous offense to their purist and engineering sensibilities. Dont worry about what the naysayers sing about. Too many people lack vision, and only see results, or how something looks on paper. I like to think most of these people are trying to help & educate, but it can come off too judging and snobby, at times. Just do you!
The biggest issue I ran into, was having to do all the measurements and calculations in an abstract dimension, via online fitment calculators and very crude physical measurements from the car, as I didn't have the tires or suspension on hand. All I had was the bare wheels, and my friend Dan to help with approximate measurements. Getting tires that worked and would make the car look like a 4x4, was difficult. The front arches are the biggest concern. There is actually quite a bit of room for rubber in the rear as is.
I would suggest that if you want to run 16s for ease of tire selection, or there is a particular wheel that you want to use thats only available in 16in; do it!
Measure, measure, measure and do some more measuring. Having the parts on hand, and a bit of patience is also highly suggested (neither of which I had). You'll probably have to do some messaging and cutting of the body work, to get a nice result. Good luck.
