I have a SD with a 48" deck. Most of our accounts wanted the grass caught. So we bought the catching system for it. Waste of money in my opinion. We haven't even put 200 hours catching grass and we have already had to replace the blower housing unit. I can't remember the part name, but it is the giant metal wheel that cycles the grass into the tube, rubbed a hole into the bottom of the blower housing. Not to mention all of the belts we went through on it and that was going very slow as well. The system might work well in short dry grass areas but anything with some density and moisture it is a pain. The hole on the blower housing unit occured because we mow a few large properties with little hills and other small dips and dives in the lawn. Has anyone else had this problem with their or suggestions? The mower is great. Still runs like new. I dont have the manual in front of me but how often should you change the air filter unit?