It is my undestanding that the 09 Smarts have a new chip which makes the car shift smoother. There is supposed to be a replacement chip for the 08's but we haven't heard much about the when.
Anyone know? I have been searching the sites (forum, blog etc.) and have found nothing. About a month ago when I was on someone had commented on the fact that the 09's have it, but I couldn't find it now.