yes full systems are swapable for the most part. there are clearance issues with teh HRC style systems on the SP1 swing arm though. I am currently running SP2 headers and a set of Sato low mids for my track pipes.
so easy way to remember
either header will fit the bike.
SP1 headers have to have SP1 slip-ons
SP2 headers have to have SP2 slip-ons
now supposedly you can fit SP2 slip ons on SP1 headers by cutting the header but i have never seen pics or heard a measurement of where to make the cut.