Q's around analog HiDef

[SRTCraig]

Hey guys, i'm considering taking the plunge into the BLU.... I've been into audio/HT for 10yrs, and have the system of my dreams. I really don't want to change things but do want to add bluray/hidef to the mix. I have a sony sxrd tv, and a 7.1 (running 5.1) amp with analog inputs.If it aint broke don't fix it right?
Anyways enough of the intro side...

*If i was to get a bluray player and use the opt/coax,

1. Would my amp give me the "core" DTS/DD soundtracks?
2. Are the "core" soundtracks better than SD soundtracks?

* If i got a player with analog outs for HiDef sound formats,

3. Is there players out there that will do "all" the new codecs? DTS-MA included?
4. Will i be able to have the BD player decode the new formats, and my amp decode the SD DTS/DD formats, without switching things on/off in the player/amp?


5. I know the answer for PQ, but is the sound that much of an improvement????

Any help would be much appreciated...