From what I read, we should have a 4ohm system. Query, Was looking at the Polk MM6501's and they are rated at 2.7ohms, but a 94db, which I believe our system is normally 92db? Lower db equates to needing more amp to power to effectuate the range of speaker? How would raising the db to 94, but lowering the ohms to 2.7 play together? Would stock unit do ok with them?