Steve,
I've had a Valentine One in both of my C5's. Saved me more times than I can count. And knowing both the number of radar sources, and the direction their coming from IS important, despite what Escort says (e.g. did you know you can ignore sources from the side and almost always from the rear??)
The nice thing about the V1 is that they have a remote display option that fits PERFECTLY in the C5's ashtray, and makes for a very professional looking installation. This keeps the "light show" out of the prying eyes of other cars who will want to tail you as their "protection" and the eyes of police who may frown upon the fact that you have one of these devices. Although I run the wires around the A pillar, under the sill, behind the driver's seat and into the power outlet in the center console, (which I have to do for reasons more related to living in Virginia (where they REALLY frown on these things), people living elsewhere should probably hardwire it.
The remote display works with both the portable wiring and hardwiring options.
Good luck!
Michael