I think 20 hrs is reasonable for someone who has done it before, 30 hrs for a first time install. Before you commit to a CGR-30, look at all the options. I put one in 3 years ago and wish I would have gone with something else. You do not have all information available on one screen, instead you have to push a button to cycle between 4 screens. My screen died suddenly on a trip and required it to be pulled and sent in for repair (about $600) after only 2 years, a problem I have heard regarding the CGR-30 from multiple users.