My G500 weighs a little bit MORE than Lexus LX470! Trust me, it's small but it weighs a lot! Anyway, the Porsche Cayenne is a decent off-roader but i would not classify it among the best. Cayenne, along with Touareg, has no suspension travel...none whatsoever! It's front skidplates are plastic. It's underbody is not protected well. It's control arms are nice, but some of them are aluminum. Let's just say that there's more smoke than real off-roading capability. In addition, from what i have read and heard, the Cayenne's AWD system is calibrated for on-road duty, while the Touareg is more for off-road.
Now, you may say...it got rear diff locker (at least in Touareg). Well, the rear locker is a clutch-based system. That is, it's a light-duty locker. Clutches wear and tear. They don't last long in heavy application, and certainly won't last long when there's great traction differences between the wheels. This is why ALL well-known aftermarket locker system are GEAR-based.