What are you considering updating the Crestron system to? In the L-series Countries and Legendary's, Crestron components are used for lighting, shade, climate control, as well as audio and video system control. Even the stereo amplifiers are Crestron brand if I am not mistaken. I am not discouraging you from doing so, but be aware that replacing all of that equipment and doing what is necessary to have those functions back is going to be a very comprehensive deal. If you simply intend to have the software or touchpanel interface updated to include a/v components you have had to change over the years, that is a different story. Providing that a programmer can get ahold of the original source code file for your bus, (may be able to through Miles Circo), than you are probably looking at $2-5K depending on how much time is involved for the number of components that have been changed and need reloaded.