The D and E model are the same pretty much except that I prefer the D model instrument panel. The company I work for use C20r2 engines in both types. We still have c20b's in three D's which are ok for certain platform jobs and patrolling. When it comes to washing though they struggle as we wash during summer. We have an F model that is being rebuilt which was purchased for stringing but I personally think that an AS350 would of been better purchase as they can pull more.