im assuming your X5 is an E53? If so, nope, it won't work. You'll need CCC Nav disks for the 120d. I believe guys have tried to copy the CCC disks and failed so getting the original disks from BMW is likely your best option. I don't think these are that expensive anymore if memory serves. You'll also want to confirm that the DVD drive on the 120d still works as these do fail with age.