I have a BG85... that I'd like to convert over to a SH85. Stihl says the BG has a different housing inside (rubber coated I think) and that it cannot be a "shredder" but instead just a vacume. The only difference being that the SH uses a shredder blade in the center of the impeller. Has anyone converted their BG over to a SH and used the shredder blade? I'm thinking that I might get the conversion kit with the blade and simply rubberize the inards of my BG's housing.