something along the lines of that manitou they put on the tomac drop bar replica thing...
It would be really nice to be able to put a nice working for on an older frame but still have the geometry and canti/v/dics hardware...
personally I found my M3's to be great and are still servicable, but the EFC was magical and if I ever get around to rebuilding the damper will happily be pressed into service again.
I went from those to some Judy "airs" in 2001, and they were... something, now running Dukes that are pretty good, but I think that 4in on a hardtail doesn't seem quite right...when you use all the travel, its feels all wonky. I think 3in is enough.