This photo shows Yokohama T125/70D17 with the rear seat down (headrest removed) and with the front passenger seat full back. Fits great. With a black interior it is barely visible.
That's exactly how and where I store my full size spare. It fit so snag no movement of tire even on bumpy roads.
Looks good, consider installing it one time as a practice event, this way there won't be any surprises if & when you really need it. My only concern is the healthy 4.6% difference between your T125/70D17 spare which only has a 23.9" overall diameter when compared to the Primes OE 195/65-15 tire at 25.0" overall diameter. A better spare tire choice would be a T135/80D16 which measures 24.8" overall diameter. Rob43
The title of this thread is kinda misleading? I keep thinking it's a Prime that came stock with a spare, which would be interesting. Instead, it's a Prime, with a temp spare (mismatched) stuffed in the back seat area, not exactly news.