Had that same question yesterday over on the general discussion board.. I learned that its more of a status thing unless you have a basic edition of the titan(or at least thats what I got out of it).. no real difference between an 2008 pro 4x and a 2008.5 pro-4x(that was my question, because I had a pro 4x). Might be some small changes for other models but nothing major that I found.Got an 08 but dont what makes it an 2008 or 2008.5