All the parts I listed on my 2nd post is all you need. The GPS must be Garmin and have bluetooth capability. The box that hooks to the GPS is also Garmin and sold separately and is called Ecoroute. They have both parts on the garmin website and show witch gps systems will work. The Nuvi 1690 is the cheapest that also has the smart routing to plan custom driving routes. The gauges are customizable to show speed, tach, battery voltage, intake air temp, intake man pressure, coolant temp, timing advance, engine load,... I think Im missing some also, can only show 5 gauges at a time. Also has another screen that shows fuel economy.