Brilliant!
I would use it if I could, but that's way outside my area. I work on safety systems, mostly advanced sensing using camera technology and none of my company's products would make your idea possible. It's funny though; as obsessed as I am with cars, only ~half my idea's are automotive related (and a lot of those are now company property). I've pitched some idea's (like a couple phone apps/social networking) to friends of mine, trying to get them to go in with me. Usually they think it's a great idea, but are even more skiddish than me. The sad reality is it would probably take me getting laid off to have enough time to bring one to fruition myself. I would love to hear about how you approach companies and pitch your idea's without them just kicking you out and stealing it. If it's not patented you basically have no protection, right?