Full Spectrum Conversion

I have an E-5, 12-60, and 50-200SWD. Will I still be able to get the same image quality from this kit after a full spectrum conversion? I'd like to use it for both IR and standard visible spectrum work. I think I'd just need an IR/UV cut filter on the lens to go back to normal visible light shooting, right?

Also, please give me recommendations on conversion shops. I've been reading the forums and have seen mixed experiences with some. In fact, I'm confused about whether I would lose the dust shaker and/or the image stabilization. Thanks to all for your help!