To use models from fpsbanana.com you need to do next:
1. Change models name and hex it(fix name in v_ and w_ mdl files)
2. Fix Iron Sight(you need to change vector)
3. Add models\materials to resources.lua precache list(to make users download it)
3.
4. PROFIT!!!
P.S Ironsight does not work well if you change model on client-side.
P.P.S I got problems with knife replacement only. If i replace it on server-side and use give weapon_ttt_knife server crashes=(