Get the V1. Don't even consider anything else. You won't regret it. I've had 4 or 5 different radar detectors (including a very expensive BEL)and the V1 is so far above all of them its not even funny. I really don't think its that big. I think it looks better than most also. The V1 also offers free* updates for life. You'll always have the latest software and hardware.
You can hard wire the cable into all your car and just move the detector around and plug it in whatever car you want. Thats what i'm planning. The V1 just uses a standard phone cable. They're cheap and plentiful. They're even available in different colors for your styling pleasure.
*you might have to pay shipping and a small fee, I don't remember.