You dont wanna look at just HP if you're trying to compage them. The Altima is lighter, barely, comes STD with 17" Wheels, which is a pkg option on the 6. They both have a nice sporty suspension. The Altiima is STD with a 5 speed stick, and the 6 is STD with an Auto, with no stick option. Also the Nissan peaks HP @ 5800 where the 6 peaks at 6000. Lower would mean it reaches it faster. Performace wise the Altima is superior. They both look damn good, the 6 has a looks that would look better if you did other stuff to it. The Altima has a little more of a refined look. I dunno, I would say test drive them, and see which one feels better.