There are a couple of good options to remove water spots, which can be very hard to remove from dark paint.
I'd suggest that you first wash the car with a professional grade car wash. Use both a wash bucket with soap and a rinse bucket for your microfiber wash towel. Rinse the wash towel frequently and keep it clean. I believe most people do more damage to their car's finish while washing and drying than at any other time. Dry with a clean, quality microfiber towel.
Buy a clay bar system, Griots is good through mail order or you can buy Mothers at most automotive stores. Follow the directions on the package. This will get many water spots but not all of them.
Next, pick up some Meguiars Scratch X or Griots Fine hand polish. Use a clean applicator pad and follow the directions on the container. Be gentle on your paint and take your time. Wipe with a mircrofiber towel after polishing.
When the water spots are gone, wax with Meguiars or Griots or your choice of waxes. I use Griots paint sealant on my black SRT-10 and remove was with a microfiber towel. I use Meguiars Quick detailer in between washes. Paint looks very deep and wet when clean.
I also use Griots random orbital polisher and their polishes pretty regularly. Very good products though not inexpensive.
Go to:
www.griotsgarage.com
Good outfit to do business with.
Good luck,
Dan