[LearnAutoBody]

The only problem I see is that you mentioned that the paint looked like it was applied with a roller. Do you have any idea of what kind of paint it might be? You may also have your paint rep, where ever you decide to buy your paint, check the mil thickness on the paint. If it is more than 12 to 15 mils, I would use chemical stripper to remove the coatings and start over. Once stripped, perform any bodywork that is necessary, and spray two coats of epoxy followed by two coats of urethane primer. Guide coat the entire car and block sand. This is just an opinion, if the coating exceed maximum thickness or if your unsure of what the existing paint is. This would obviously be the long version. It depends how much time and money that you want to invest in your project.

As far as clear coat, here is a 3M video click on paint finishing videos