Motorheads don’t want to hear it; refuse to believe it — but ugly realities are coming down hard on the ‘09 Camaro that will very possibly cause GM to pull the plug before the first one ever rolls off the line. Doubt that? Consider the stillborn rear-wheel-drive next generation Chevy Impala — nixed because of concerns within GM about the possibility of meeting the pending (2012) 35 mpg fuel economy edict recently passed by Congress. A lighter front-drive car with a V-6 instead of a V-8 can make the cut; a V-8 RWD Impala can’t. So it’s gone. So is...