I installed it a couple of weeks ago in my spec. B. This guy is a lifesaver as I have an iPod and SIRIUS. I was not skeptical with the product or concerned with installation. Just get it. I rate his instructions w/ pics. A+, and they are photocopies. Your stated concerns are not relavent, believe me. The NAV and climate controls are individual, unique plugs. Give yourself a 2-3 hour window, follow the instructions and take your time.