Phil, it looks like the dealer should study up a bit more about amplifier and preamplifier technology. The possible(although unlikely)problem with the receiver would be shutting down because of overheating. Clipping wouldn't occur unless the designed power limits were greatly exceeded, and impedance wouldn't be a factor in that. Use the receiver for what might be an interesting comparison.
The speakers should be situated identically as nearly as is possible and should be, for example, AP-AP, rather than both inside or outside. Also, the volume level should be as equal as possible, which can be difficult with speakers with varying output at different frequencies.
