How will it lead to total civil war? All it will lead to is the police stops taking people's property without a court order or they risk getting shot.
Second, the statement above didn't say much about requiring a warrant to take people's property - how do you get to USA v2, where that law is in place? Do you shoot enough cops, so they would change the law? What kind of wild-west mentality dwells around there, anyway? How about writing a petition? How about sending (e)mails to your congressmen, or whatever people with that kind of authority you have in US?
Sure, why not? Most cops don't train that much with their weapons, and there's a bunch of crazy rednecks out there who train constantly with various firearms. I'll put my money on the gun nuts against the cops. Check out some YouTube videos by guys at pistol ranges. Also, cops only train at standard ranges, where you stand still and shoot at a non-moving target, and don't generally do combat training. Face it, cops aren't soldiers; they're just thugs with guns, and most are about as skilled with guns as your average ghetto thug.
As for your bet - the paradigm would shift from bullying all people to bullying frail people and avoid rednecks, as far as the violent cops go. This would hardly solve the problem.
Most cops only train with their pistols once or twice a year.