Yes it is easy to do, use the sand paper and key the paint ( make not shiney)
When you paint it make sure you wear gloves or you will look like a smurf for a week or more. (that if you use blue) I would not have black as van will be very dark.
I have a purefreedom system in one of my vans, nice guys, seems there prices on systems is ok, but try for ionics status on there online shop which I am shocked at.
Ian