I've installed JftS after the K1R and the only bugs I had were early mentioned dantooine Matale Grounds issue, and some minor BOS part bugs, wich may or may not be BOS specific - not sure about those (companions on Orion where there should be none, abnormal character levelups inbetween BOS parts (skill grows like +10-20, levelup each time on zone reentering (actualy funny, after lvl 20 you became 0 with lvlups to 20))). Anyway the main story was running smooth and nice:)