ladybird hrc copy clearance issues

does anyone with this gorgeous system know why they are sold as sp2 only fitment? is it because the pipes fit into the indent on the sp2 swingarm and not the sp1. my new swinger has the cast front section from the sp1 and seems an impossibility to fit those pipes in behind?. For those that have purchased these was it through simon kobe. I'm running high level harris titatnium at the moment but I am seriously tempted.