Hi, i don't even think you can compare the 2 at all. A BMW with DSC (Dynamic stability control) is one of the most incredible vehicles to drive. I have driven both X5's and X3's. I have actually been on a race course with the X3 to demonstrate how well the DSC works in the rain and cornering at high speeds.
It was incredible with little to no body roll what so ever. It knows when the car is is about to kick out and brakes the appropriate wheel that is losing traction and gives traction to the other wheel while limiting the throttle as well. This function can be turned off with the switch of a button as well if you want to have a little fun going around corners.
The BMW is like nothing else out there as far as on road performance. The all wheel drive is great as well.You just turn off the DSC and it has great traction for mild/moderated off roading.
In my eyes the Lexus just has that cheesy Toyota feel to it through out. Of course the KJ would tear up both of them for moderate to extreme off roading.
We have a 323i sedan and a 03 Renny. On rainy days we use the Bimmer because the KJ is awful in the rain compared to it. I'm still in shock how easy the back end kicks out in rain with the KJ,granted I still have the stockers on it. ??Do you guys think changing tires make that much of a difference in the rain for the KJ??
By the way BMW tours the nation with free test drives and the Ultimate Drive course that I mentioned above for free while donating $1 for every mile driven towards Breast Cancer. Here a link so you can see if it's coming near you.
http://www.bmwusa.com/bmwexperience/eventsandprograms/