I fully agree with you that weight can make a significant difference in how the boat handles and "flies". Yes we have room to move the engine forward which we will already be doing by adding the tranny. We could use a 9" shaft but that actually may be too far forward when you add the trans length to it. We have the room to do it but I think that it is too much. We should be adding around 250 lb over what he has now but moving the engine forward will offset most of that. If we did the trans in the standoff box, I think that we would notice a huge diff in CG but otherwise the boat should not react adversely to the additional weight. The hull has been tested with more tail weight then we are talking here and still flies very flat in the rough stuff. Plus we have the ability to move the fuel tanks forward if needed.