?Cadillac?s new SRX: More power, new features? Headlining the list of significant updates for the new 2012 Cadillac SRX , 5-passenger, 5-door SUV is what will now be the sole engine offering in the U.S. marketplace. The new engine ? code-named ?LFX? delivers 16 percent more horsepower while also providing more low-rpm torque. This latest…