For resale value purposes only, that is a great reason to go with the sports kit AND the fact that it is a "newer design".

Here in Los Angeles, CA there are only a few X5's with aero kits, and the price I can get it is much less than $3k. Right here I can get the original aero kit painted and fitted for around $1300 USD.

Then again this is my first X5 (08 4.8i Space Grey), and I am thinking of having the Aero Kit installed for the first time. Either way good luck!