The amps in those receivers are a big step up from what's in the 919/1019... if I were staying with Pioneer, those receivers are the ones I'd be looking at. But I can't afford those, so I'm probably not going Pioneer next time.
After my last post, I decided enough was enough - I wanted to see where my home theater's limits were. I still hadn't tested the IXL to reference level, so with the knowledge I had the LFE boosted by 5dB I ran the receiver up to -5dB and let it have some test tones between 10Hz and 20Hz.
As soon as I started testing, the receiver's fan came on. This was in stereo - I haven't gotten around to trying the full 7.1 at this level yet. The IXL did fine... no signs of distress. The 919 didn't shut down. But the fan did not stop until well after I did. I had to stop when I detected the smell of voice coils getting too hot, and then I realized - my left and right mains were also getting these test tones. It was from them the smell was coming. So, it looks like the 919 can indeed get powerful enough for my speakers in stereo mode.
But, the receiver fan ran a long time, even with the two 140's on top turned on. And I still wasn't at 0dB on the mains. It did ok in stereo, but I still feel like it would fall on its face if I let it run all the way up to 0dB in 7.1 mode. So, I set all main channels back to small with the crossover at 50Hz. Best to offload some of the power demands to the subwoofer in my system. At least, that will keep the fan quieter.