I dont see this working very well unless your parked on extremely flat and level ground. The air is always going to go to the path of least resistance, so if the car is leaning towards any side its going to have more weight on those tires and not fill up evenly. The same problem will happen with deflating, the ones with more weight will deflate faster. only way to fix this would be to put a passive regulator on each tire so it would shut off when its at the desired level. But when this happens you can no longer use it to deflate, unless you had each of them on a small section of hose with quick release chucks on each tire so you could pull them off, but by this point its getting rather expensive. Its a good concept, and could be used to fill up your tires and deflate quicker, but i would still use something else to get my pressures right where I want them when inflating or deflating.