There are only two things you have take care of:
1. Only the online activation will be available (no more mail activations possible). If you don't have internet in your car yet, you have to establish a internet connection the one or the other way.
2. Whatever you do, the limit is set to 20 activations per license. As you have exceeded this activation limit, there'll be no option to get another activation.
So be careful. If you decide to share the license key with other people, this is your problem.
Unfortunately, my server is currently down and I don't have the option to bring it back online until next Tuesday for some reason. So, please be patient.