I am debating the purchase of either an 08 or 09 GL 320 Diesel. I am aware of the few standard feature improvements for the 09. I am also aware that the Bluetech motor has much improved emissions while also facing a $4000+ fuel filter replacement in the future in addition to the AdBlue (Urea) periodic services. Is it worth stepping up for an 09 or should I focus on finding an 08?