I had a look at the settings on mine, they are about the same perhaps a little lower. I took the sub limit off last night and tried it again. An interesting thing happens, I can get the 350 to as you say give some port chuff, but the 175's do not, turning back on the sub limiting eliminated this. the best part is what happened next;
We then went over to my friends house; he has the B&W Nautilus 801's (they have 15" down firing subs in the base of the speaker tower), these are being fed by Krell 700CX amplifiers. At Reference level (0db) the 801's subs clipped. You know I don't feel so bad now that I see a pair of $12,000.00 speakers doing the same thing. i think that this DVD will push a lot of peoples sytems harder then they ever thought possible.