I knew I'd get some quick replies. Thanks for posting!

1. I'll double check if I'm set to 4 ohms or not and report back. It's been a while since I set it up. I could be mistaken. I did do a lot of reading at the time on these forums when I set it, so I thought I had set it properly. (just checked and it's set at 8 ohms. I recall my reading now.)

2. The Yamaha is rated to 140W with only 2 channels driven. I'm guessing that drops quite a bit with all 5 driven, no?

3. I do listen fairly loudly. Mostly blu rays and gaming, so there's usually a lot going on in all channels.

4. Given this information, do you still think further amplification won't be worth while?

Thanks again.