My '07 has the second version of the RBK (see this page), the version without the cassette player and Balance/Fade dials. On the build sheet this is listed as AM/FM Compact Disc Radio w/Chgr Ctr although I don't have a disc changer. I also don't have the infinity speaker package, so there shouldn't be additional amplification required. I bought a single DIN head unit, the BOSS 616UAB, which is rated for 50Wx4, and the necessary cable adapter from Scosche. The new head unit power on and seems to function normally, but the speakers won't play any output. The head unit is putting out ~110 ohms to each speaker. I don't have an easy way to compare this to the output from the RBK without manually wiring it to a battery. Am I missing something? I've seen others put in 40W units without issues, is mine just bad?