What is it about muffler shops and modified motoring that go so hand-in-hand? Now, I've never lived much outside of Southern California, so I've no clue how widespread the phenomenon really is.

General Motors has managed to wring out more horsepower from its 3.6-liter direct-injection V6 and get better fuel economy, too. And the 2012 Chevrolet ... head and exhaust manifold into one ...