how do I find out if I have a revup motor and which is better
thanks

The rev-up is easy to identify by the extra set of cam phase sensors and exhaust cam actuators. Google something like "VQ35DE rev-up differences" and look at the images.

"BETTER" is subjective, a built non-rev motor will smoke a stock rev-up. The rev-up does allow for more mechanical precision by changing exhaust cam timing but the differences will only be felt in a naturally aspirated situation. Once you add boost it almost literally has no meaning since the restriction is the strength of the rotating assembly.

There is also the problem of higher potential for oil consumption from the rev-up due the the increased redline couple with flimsy factory piston rings.

Personally I love my rev-up motor.