AK,
I can't tell you that the exhausts will definitely interchange or won't, but I'm running an exhaust marketed for the Sabre on my '95 VT1100C. All I had to do to get the V&H ProPipe to fit my bike was fabricate a new muffler hanger bracket. If I had to bet on it, I would say that's all you'd have to fabricate to make any 1100 exhaust fit. Even though some of the 1100s are single crankpin and some are dual, I don't think the head port configuration is different. The only other reason I can think of that a set of pipes wouldn't fit would be due to interference with footpegs/floorboards or engine guards.
Brian