Ohms-speakers

[MR.G.]

Sorry to omit details. I am running the 4 polk 4 ohm speakers off the Alpine head unit that has 18 w/RMS x4. I am NOT running an amp because the guy at Audio Connections told me that the 18 w/RMS in the Alpine was stronger than the Haes set-up. Something about using a power output measurement standard that is NOT the same equivalent (less power than RMS rating system).
Tks.,
MR.G.