Re: I might be wrong, I may already have a biposto subframe (ducatilover)
Biposto subframe = steel+mounts for passenger pegs, mono = Al, no pass. mounts.
also has different plate for seat latch (surprisingly only $11), spaders, screws.
going from bi to mono requires new mounting of ECU (cable length different), this took me a while to figure out how to cleanly mount and get to fit, inner fender different (different mount points), tool tray not the same.
I know as I converted '00 996 to mono