You can run any of 1, 2, 3 or 4 but you would have to change some of the fittings on the ends. Now i believe you have an 04 lever body. You can not fit any of the new lever blades in 04 lever body and an 04 lever blade will not fit in an new lever body.(obviously). But you can run any one of the above levers with any slaves(again some fittings may need to be changed for instance on the deng slaves). So basically if you have 04 slave pistons(the bit that the pad goes on) you can simply buy a new COMPLETE lever and then bleed it. Or as someone else mentioned if you love your 04 have a look on ebay or the far sale section on here. That may sound really patronising but its not meant to be.. sorry