Hi Dan,
I understand that completely - I'm the same way. I recently installed an in-dash navigation system in our family car. It had an optional wire that can be hooked up to the speedometer to track you while in tunnels/lost signal areas. Hooking up that wire meant removing the entire instrument panel - a lot of work. And who needs GPS in a tunnel? Well, I couldn't help myself and hooked it up anyway
In this case, I'd just like to know more before proceeding.
Keep us posted on your progress.
Kevin