Yeah, this sounds quite interesting.
If you are successful in your purchase here in the U.S. post a comment here and let us know how it went. I might just make a purchase myself....So I am correct to say that first I call Lego Customer Service, then I ask to "order some parts" or should I mention "Lego Direct", and then I proceed to list part ID's.
I was thinking the same exact thing. I have been wanting to order the 8297 Offroader for it's steering/suspension components + tires off the web but it is quite expensive. What was the price on the four tires?