Mercedes/smart believe that the current cdi engine to not provide enough power to pull the new generation smart ... they are waiting on a new cdi diesel "if" they decide to build it ... the current 08 cdi cars in europe currently use the engine found in my 05 smart ... after having both cdi and now mitsu engine i would HIGHLY recommend the mitsu power plant over the cdi - the mitsu is cleaner, far more reliable, and much easier to live with on a day to day basis, has a beautiful engine note and gets good fuel economy.
james