I found the same problem with it [cv boot driver side] this morning @72.5K. Most of indy shops won't replace just CV boot but the entire axle. Reading some articles about DIY CV Boot replacment but still can't do it myself!
I called my auto repair friend he said he will replaces just CV Boot for me and charging $100 labor for each site [I checked passenger side and CV Boot doesn't look good even though it's still clean]. I have been told that not driving the X if I really need to. Calling BMW Part Dept: $85.00 for each side CV Boot kit including axle nuts.

So here are the options

CV Boot replacement:
A. Buying 2 outer CV Boot Kits for both sides = $170.00 + $200.00 labor = $370.00

Replace new axle:
B. Buying 2 OEM axles for both sides = $1100 at dealer. Bring the old axles back to the dealer that save you $100.00. Labor cost $150.00 for both sides. Totally I will pay at least $1150.

Therefore, i will take option A.

You better not buying cheap alxe $80.00 < $160 via ebay or some others store, your X will vibrates after you replace those aftermarket axles.

__________________
================================================== =======================================


BMW X5 2004 - 2005 MB E320
BMW 1999 528i/ 1998 Nissan PathFinder (sold)