I bought an electric pressure washer, a foam cannon, a quality wash mitt on a pole and a de-ionized water system. My wife and I can wash both the Y and the 3 in about 10 minutes total. Rinse with pressure washer, foam with cannon, wash with pole, rinse with pressure washer, hook up de-ionized water to pressure washer and rinse. Done. I have quality quick disconnects on all hose fittings so I can hook up & tear down fast. It's faster than driving up to the car wash and we don't hardly even get wet. It helps that I put a DIY ceramic coating on the 3, I still have to do that on the Y. Use warm water in the rinse bucket in the winter to help keep your hand warm if you use a hand mitt. (Which we only use for the hard to do spots.) You can wash two cars in only a bit more time than one; most of your time will be spent setting up & putting the wash gear away.
I have a gas pressure washer, but it's bigger than the electric, more pressure than I want, and a general PITA for washing a car. I got a small Stanley and threw out the cart. It's so small and light the cart & wheels just got in the way anyway. Don't make the mistake of washing & rinsing with de-ionized water. That would get expensive. Just do the final rinse with it so you don't have to dry the car. I figure it will cost me about 50 cents a wash to eventually replace the filters.