Newbie Considering 2011 X5

[BMWREXPENSIVE]

New guy here. My wife has a 2001 325Ci and we are considering getting and new 2011 x5 3.0 for her. A couple questions - the only real noticeable advantage of the Sport Activity Package over the Premium Package are the 20" wheels.

I know there are other items included (sport seats, black headliner) but are the 20" wheels really worth the extra $2500?

Are the 20" wheels on the sport activity staggered and are they wider than the 19" wheels on the Premium?

This car will be primarily for my wife - will an X5 have a smoother ride when compared to her 2001 325Ci? We live in Houston and the roads are pretty rough and she is looking for a smoother ride.

How much rougher will the 20" wheels on the sport activity package be compared to the 19" wheels of the premium package?

Lastly, I am 6'4" with somewhat long legs. Per BMW website the X5 actually has less leg room and head room than a 535i and 335i. Is this really the case cuz I am not going to be crammed into a vehicle. I seem to fit fine into my wife's 2001 325Ci.

We do not have to purchase immediately, but would like to start seriously considering purchasing in December. Would love to come across a CPO 2011 that someone had to unload in December to get the 6 /100,000 mile warranty and save a couple $$$.