Rmeuropean dot com apparently has the GKN Axles for about $250-$280 range:

X5 3.0i Sport Utility E53 3.0L L6

Hey all, so I went ahead and ordered from CVJ, they are supposed to arrive today! Yes I am going to replace the diff seals while I'm there, and I am pretty sure that my axles are original parts, they look like they have been on there forever and seem to be very well built inner boots still look new, not much corrosion etc. So I am pretty hopeful that the core charge will be reimbursed to me. Wish me luck on the job! lol.

Harbor Freight has the 1/2" earthquake air impact. I have confirmed that it can remove the axle nut without issue. Did it on my X a few months back. Took a few hits, but got the job done.

It's like $70, and they have a 20% coupon all the time, and will accept it from your phone. No need to print even.