If you're on water restrictions (even if you're not), get some Optimum No-Rinse (ONR). I've been a car fanatic for 35 years or more, and I thought this stuff was a joke prior to seeing how well it worked and then trying it myself.
You need a bucket, 2 gallons of water, 1 small and 1 large microfiber towel, and 2 capfuls of ONR (I usually use 3-4 capfuls in 2 gallons). Follow the directions, and the car will look beautiful when you're done with no scratches. The surface will be glossy and smooth.
Also, my detailer just recently went berserk after I told him about ONR (he’s been detailing for more than 20 years, and he thought I was crazy when I told him about it), but after he tried it, he loves it. He talked with Optimum Polymer Technologies, and they sent him some trial packs of their products. He recently did my M5 and finished it off with Optimum Poli-Seal, and this stuff is incredible. I had previously only used Zaino Z2 or Z5, but Poli-Seal seems even better than Zaino to me. The flake in the LeMans Blue paint just leaps out at you it seems. The surface is incredibly smooth. Good stuff.
On Optimum's web site,
Optimum Car Products, they have the 32oz bottle of ONR, but I buy it in gallon sizes through Amazon (think it is Palm Beach Motoring Accessories).
Chuck