Greg, I took the time to check p.119 and found that the FTC required ratings were 130 watts into 8 ohms and 170 watts into 6 ohms. The 4 ohm rating they show was not by the standards required by the FTC for all amplifiers sold in the U.S., and presumably it couldn't pass at 4 ohms, since that certainly would have been specified. The unit doesn't carry an official 4 ohm rating.
Not that the lack of such a rating is crucial in real world performance. The Onkyo 3010(the 3008 wasn't tested)tested
here did about 257 watts into 4 ohms. The Onkyo and Pioneer receivers you're discussing have substantial and similar 4 ohm capability despite the lack of the 4 ohm rating. You appear to be paying far too much attention to speaker impedance ratings as they relate to amplifier requirements.
