The Vikings are just under the cap with less than $900K space. Yet they just signed Za'Darius Smith for $14M. IMO they must either restructure Hunter's contract or trade him because they can't afford both the way it stands. Hunter would give the Rams a long term solution at edge opposite Floyd. With all the money the Vikings need to clear for their rookie pool and Smith I don't see them being able to keep Hunter which is why their best option is to shop him.
Hunter and Floyd off the edges would be a formidable pass rush, but when you add in AD and Gaines it would be deadly. Hunter appears to be over paid on the Vikings compared to his production. But I think he would blossom on the Rams' DL. I could easily see him signing a $60M contract for 4 years with a 5th year void added in to spread the cap hit.
If it comes down to Wagner or Hunter, then Hunter wins hands down. As nice as signing Wagner would be, IMO he's a consolation prize signing. Really improving the team would be Hunter and I'm not sure even Snead can squeeze both. Having Hunter, Robinson and OBJ would be tremendous off-season signings.