Didn't the Katana 1100's use a dual exhaust? If so, then you could use the header as far back as the collector. Then you could possibly attach the TL's split to that. Really, I think you could better spend your time and money on something else. But it is your bike.
Could swear the old 1100 came out with dual exhausts for a year or so...if so, do you want to just dump the stock pipes and install the TLs??? Like the guy said, if you are talking about putting on stock pipes, muy weight.
Normally, dual exhaust are installed on a four to help with noise level readings, as opposed to performance.
Grab an orr and hop in the boat! I have been spw Hindle on a dual high & tight (splitting the manifold) for the OS gsxr's. As of yet it's a nogo, but if you e-mail 'em (along with a few more showing intrest) they just might budge for a few units!