I finished up the rear conversion (for now). This is is about the best I can come up with based on some limitations I ran into. I wanted to add the the 09edge grips so the rear gussetts would slide right into them but, the sled has Snow Eliminators and there is no way to make the 09 Rail edges fit without major rework.
With the half round cut outs on the sides of the stock tunnel, I didn't really have a way to cover the huge open areas up (without swapping out the entire rear extension). So, I ended up using the stock tail light and flap again.
I used a 2009 153" rear bumper, the rear gussetts that will have to be welded, I trimmed out the holes in the footrests just like the 09s and newer. Here are a few pictures of what I came up with for my daughter's M5.
Oh yeah, I have several items I planned to use that I won't be using. A used 09 rear flap with a brand new tail light assembly mounted into it, the 09rail edges that I wasn't able to use, a flattened stock rear heat exchanger and the rear close out piece for the tunnel that didn't work out for my circumstances. If you can use the parts in the last picture let me know and I'm sure we can work something out.