Last year, I plashed out on a Metrovac AirDuster for my PC, as I was tired of buying the disposable cans of air. It's incredibly powerful, and I'm thinking about pressing it into service for drying the car. It might not be ideal for such a large surface area, but it would be great to blast the water out of nooks and crannies like side mirrors, doorshuts, etc - all the places you find those annoying rivulets of water appearing from the moment you think you've finished and put the drying towel away.
On the subject of drying, I think I'm going to need to find a water spot remover. I've only ever used filter water for rinsing the car, but still have what appears to be water spots appearing, which I think have come from rainwater. Even after a wash and dry, you can still see them in the right light, which is bugging me.
As I've got their Crystal Serum ceramic coating, I tend to stick to Gtechniq products now and see they do W9, a water spot remover.
Anyone used this with any success, or any other removal products? My biggest concern is that it appears you are meant to spray these products on a dry surface and then wipe them off. I always feel like any procedure like that risks swirl marks, but I've never used such a product before.