No less than five trim levels of the ultra-luxurious Infiniti M sedan are offered for 2013. The M37 and M37x with all-wheel drive are outfitted with a 330 hp 3.7L V6, whereas the M56 and M56x are spirited by a 420-hp 5.6L V8. And finally, there’s the M35h, a hybrid whose total output comes to 360 horsepower. The lone transmission is a 7-speed automatic.