It's not easy to tell if you don't have the original invoice of your car. The easiest way is to look under the passenger seat for the box (see viewtopic.php?f=13&t=488
). With a "Premium" phone you usually have an emergency call button in the ceiling. If your car is older than Q3/2010 and you could pair your HTC One X without my app, you surely don't have a "Premium" phone.
The problem you describe is extremely unlikely with a "Premium" phone, while audio problems are common with Handsfree profile operation.