I'm trying to decide what mower purchases I need to make this winter and this would affect my lineup. I have a '98 Lazer Z HP w/ the 48" deck and 18 hp Kohler engine. 1050 hours and the engine may need some work done w/i the next year or so. Is there a way to upgrade to another Kohler with more power/torque if I wind up deciding to replace the engine anyway? I wouldnt' feel as bad having to lay out cash if I got more power as well. I use it for mulching and could use more, of course. And could Exmark provide a list of suitable models?