CCV here is maybe $150 for parts and with diys, first time, maybe 3-5 hours depending on what all you have to learn to do...maybe 5 hours reading diys!
Disa's rattle, I know, haven't heard of them buzzing...electric type buzzing, or maybe buzzing coz there's a leak in the 0-ring...if you have one. If not, I believe they come from the factory with an rtv sealant.
There's an epoxy fix for the valve pin if it gets loose, but don't know about that...haven't needed it yet.
Of course, if disa is out and you're trying to save it, clean it too...a little time and maybe an 0-ring.
You sure it's disa? Have you isolated sound with a stethoscope or hose?