The reply from Marantz is as expected as they want to sell the PM series for the much higher profit margin. From what we know so far from your posts:
Listening habit and environment - small to medium size room, mostly listening at lower SPL (sound pressure level)
Equipment preference - Always want an integrated amp for music listening
Influence - Probably by subjective reviews online, forum talks, manufacturer customer supports etc.
Subwoofer experience - Not good, but the sub tried was a bass reflex type made by Dali.
Now look at some facts:
Listening at low SPL means more power will not likely change anything because the speakers will not be taking much power to begin with, unless and until you crank the volume right up.
Customer support is not the best place to ask the kind of questions you are asking. Think about it, what do you expect them to say other than telling your they have better components and specs and should therefore sound better? Actually they could have told you that for 2 channel listening, the SR6011 can provide much more power than the PM6005 or even the PM8005. The PM8005 is only rated 100W into 4 ohms. On the test bench it could probably do a little more, say 135-140W. It is at least limited by the smaller power supply that is designed for 2 channels. They will
not be more dynamic than the more powerful SR6011 in two channel stereo, otherwise it would defy science.
I copied the comparison table of bench test data (all by Sound and Vision) that I posted on another thread, you can see that the SR6006, the predecessor of your SR6011, was benched tested to 157W X2 at 0.1% THD, at 1% THD it was able to produce almost 200WX2.
http://www.soundandvision.com/content/marantz-sr6006-av-receiver-ht-labs-measures#zoZE7CwGCTLjp8Ku.97
Regarding your not so good experience with the subwoofer, you might have made some common mistake in setting it up with Audyssey. If you are to try again please do the following:
- read the instruction of the sub so you know how to bypass all internal bass management features of the sub such as setting the crossover to maximum, and disable all filters if possible, and if not, set them to points where such built in filters will do the minimum. This is to avoid those features to interfere with Audyssey.
- read Audyssey's online instructions and follow Marantz onscreen instruction, to the letter, when running it through all 8 positions.
That Dali subwoofer you had tried before was a bass reflex type, you will likely find the sealed type such as the low budget SVS SB1000's sound tighter and more musical.
The integrated amp you are thinking of buying will not give you more power than the SR6011 for 2 channel applications. In a "blind" test, I am quite sure most people will not be able to tell the difference between it and the SR6011 if the comparison test is setup properly. However, if you always wanted an integrated amp, I will say this again, go for it. I have all kinds of preamp, prepro and power amps and I like them all, though I cannot honestly tell people that one sounds better than the other.
My final recommendation is, go get your dream integrated amp but do not give up on the SR6011, it is a very capable mid range AVR that is very capable of improving your in room bass response. It has a very good DAC build in and can play just about anything in digital including DSD files.