It’s the mounting. The 09+ bikes ran the rear cylinder under the frame and had different mounting points. It’s been done but it take a decent amount of work.
Khroneworks or SS powertune duals are made for your year bike and run under the frame like the 09+. That’s your best option.
V&H also list Power Duals for 08 and earlier, but they are a completely different design. It runs a pipe off each side and do not go under the frame. I have them on my bike and love them. The 09 and later don't fit due to the oil pan and frame width/mounting points at the rear with mufflers attached.
Thank you for the input.
I recently went d&d and took the v&h off my 12 Ultra.
I was going to put them on my fiance's bike, the Road King, as a surprise for her, since they are in such great shape.
Oh well, guess I'll sell them!