As I understand it, there is a Stewart F7 and an earlier version Stewart - Kato powered F7. It seems that the Kato powered is a preferable model. What exactly is the difference and when were these models made? Also, I see that Bowser - Stewart is about to release a new run of the kato F3/F7/F9s. I see there is a detailing kit for these Stewart F7 models. Perhaps it will bring it up to the detail level of other models made today. Are there other good tips for improving these units? I want to add a pilot plow on my Espee Black Widows. What version of that is recommended? I have a series of these engines and I am trying to learn a little about them as I will be operating them on the club layout soon. I understand that the Intermountain or the Athearn Genesis engines have "out-classed" the Stewart models, but I thought the Stewart engines ran very well. Thanks for the help.