I am buying an Exmark Turf Tracer HP with 48" deck. I want to mulch with it most of the time. I can get it with a 15 or 17 hp engine. I save $300 by getting the 15 hp engine, but I am concerned this is too small. Does anyone use a 48" Exmark with a 15 hp engine? How does it do for mulching? Thanks again for all of the help.