Yes, the KBB means very little when it comes to the MKI, except maybe when you are registering it with the dmv. Then you should make sure that you show a price for your new MKI that is more inline with the KBB so that you don't get charged an arm and a leg for yearly registration.
I've seen very low mileage MKI's go for over 5K on a regular basis the last several years. But they need to be carefully inspected as I have seen a number of rip-off ads claiming low mileage on cars that are beat to death.
Also, if you have a MKI in good condition and/or mileage, and it ever gets totaled, don't let your insurance company screw you, as you should be able to easily prove its real worth by getting copies of sales ads for cars in similar condition (the insurance company is most likely to try and claim KBB as its value).