have same issue with mine, its the 46" deck. I wouldn't say the mulching kit made much if any difference, just changed where the dirt, dust, and grass clippings flew out at. I started a thread a year or so ago on here about this issue asking about buying or building some form of deck curtain or baffle around the bottom of the deck, however I have not done it, just living with the problem and learned not to mow when its windy