I would order the one that's right for your bike (mono or biposto). If the mono can is in fact shorter, you may run into fitment issues.
I have a full zard system and it's great. It completely eliminated the flat spot on the rev range (no PC3), and I have been told it's loud.
is your bike mono or biposto? u have pics? and no pc3 needed? the reason i asked about the mono or biposto is the mounting points are the same to my understanding and other than a shorter subframe there is not that much of a diff. i have a bi right now but plan on changing to a mono. im worried that if i buy the biposto set up it will not look proper with the mono stuff to where if i buy the mono stuff and it doesnt look good it will force me to go ahead do the mono swap!