I was commuting around 150 miles a day and occasionally use the car for road trips and had the same concerns about not having a spare. (2013pp with 20" wheels.) I once had a puncture in the sidewall and was just able to make it to a tire store using the factory kit with slime and compressor. I said never again. I had to replace the tire from the sidewall puncture, so I ended up buying a new set. I kept the best one and had it mounted on a factory rim I bought on ebay. I just keep it in the trunk with a cheap jack so if I ever have a flat, I can swap out the tire and keep going like nothing happened. I don't have to worry about tire diameters and widths, and I can get the flat fixed at my convenience.