Because if you're into lowering a car, you'll have a buncha problems. So if you plan to lower the car more than 2 inches, don't buy AWD. Also, if you're into body kits, buy 06-08. 09-13 has WAY fewer kits so most go vertex for those newer years.
Love my 09 just be sure when ordering things like aero for the front lip or when looking at grills you specify 2009. Our front end changed a bit from the 06-08 guys.
Side skirts and rear aero your good to order the 06-08 stuff