I've gone beserk (for me anyway, not much of a mod person) with the mods, B9, Firespitter, Subassembly, Carrier mod, and maybe quantum struts, KAS, and airships. I haven't done much with the mods, but it will be a good feeling not to have 1/2 zillion pages in the structural tab when 0.21 comes out. Did that make any sense? EDIT: I'm pretty much doing nothing but waiting.