Z5500 users, I need some advice because I'm thinking of buying this myself for my room's DVD.

Questions:
- Does digital connection improve the sound quality ? By how much ? In what area ?
- Does ditigal connection makes the bass less boomy (more accurate) ?
- Does Dolby Pro Logic for music only apply to digital connection ? What about in analog connection ? What mode is available to make the music play in all speakers ?
- What difference between Coax & Digital ?
- Do you know if there are many complaints about reliability of the product (being damaged/dead sub, etc. like S750) ?
- The subwoofer, is it backfiring/sidefiring , or floor-firing ?

So far that is it. Thanks.

Guys, as some people might have noticed, I just got my Z-5500.

But some questions:

I connect my Z-5500 to my DVD player with optical cable in my room sized around 3 x 4 meters. But I set up the 5.1 using only half of the room. Using DTS/D5.1 to watch DVD, I often have to set my volume 70-80% most of the time to get quite loud. But even at 70-80%, this is not considered VERY loud or insanely loud. I keep hearing that Z-5500 is doom loud, but I don't really see the case here. The fact that I have to set 70% volume to get quite loud on a 500W RMS speaker is not really that powerful, isn't it ?

What volume do you watch your DVD to get "quite" loud ? What is your room size ?

You must know that Z-5500 has another "BOOSTED" volume after the normal 100% volume, right ?
What is this ? Does the setting actually push the speaker beyond its rated power, or is it still within the rated spec ?
The fact that Logitech use the term "BOOSTED" is very ambiguous to what it really means, and the fact that this hidden setting is so easily found by users also becomes another question whether it may be used or not.

Anybody has better ideas ?