I have (with pleasure) non runflat tires 19" Dunlop Sport Maxx.
Very comfortable and quiet (65DB).
I have order my car with the spare tire (with car jack), these have been placed under the floor.
Unfortunately, it takes 60% of the space under your floor, but saves you a lot of trouble when you're with a flat tire.
The spare tire is from "Maxxis" 135/90R17 and is fixed to the bottom.
In the wheel a Styrofoam block that I have incorporated some tools , including my bottle of oil is inside. covered with a plate.
Also the car jack was in a large styrofoam block , but I did get out, space savings, and clamp down the car jack behind the spare wheel.
I still quite a few loose belongings next to and above the spare wheel.
