Only RoF changes with model switching, and technically, it shouldn't. To change anything else other than model or texture, you'd have to decode the attributes.rez .txt files. RoF changes along with model, in which you can find a tutorial for model switching in the stickies. For model switching, check out my tutorial called '[Tutorial] Model changing'.
Hope I helped, Gallo.
P.s, There is no advantage in switching armour models, you will not have more defense against enemy bullets. It's visual. and same with the grenades, only visual changes. Which isn't much.
Again, Gallo. If you need more help, don't be afraid to PM me, I don't bite... Much. :3