Upgrade MOHRadiant?
 

Is it possible to download and install new textures, weapons, etc.? eatthis:

If anyone is offering them, but I haven't seen any to date.

new textures is easy as you create these like you wouls a custom skin, if you look around you will see there are at least 2 new sky packs out numerous ladder packs and some other building textures.

if you need anything specific try the maps and mods froum and someone might help you out.