Given they make such a deal about the 460, I hope they mean RMS. And you're right - it can't be in the head unit w/o some pretty serious heat sinks up there. I suppose the only thing I'd really be losing is the in dash CD and tape deck. Given that I haven't owned a tape in 10 years, and the empeg will do away with the need for the CD player, I suppose I've nothing to lose. It's interesting, though, looking at pictures of the dash, there do appear to be 2 DIN sized slots ... http://www.fordvehicles.com/images/popups/popup_mustang_machsound.jpg