Can anyone give a recommendation on a good tire inflator that plugs into the 12V connection? Particularly, I like the ones that let you set the desired PSI so I don't have to babysit adding air to each tire. If it's part of a tire repair kit, even better. Also, how close to the max PSI do you inflate your tires? The Goodyear tires on my Model S list a max PSI of 51.