Wondering what other subframes will fit on k3 1000 with little or no modifications besides the obvious k4 subframe? Any help would be highly appriciated.

I believe the 05-0? 750 subframes fit them, but verify that somewhere else. I'm not 100% sure.

its the 04-05 600 and 750s that fit, but you have to use the 03 04 1000 set moutning brackets as they are different in mounting location on the rails