I used the D&.D kit for 2010 & 2012 so I would have the right size bungs for the O2 sensors. The header pipe with this kit offsets the muffler to the right so an offset is needed to move the muffler to the left and down to align the muffler with the stock muffler hanger located at the rear of the trike. – See more at: http://bikernettrikes.com/pages/TRIKE_MUFFLER.aspx