I have a question regarding pre-pros and receivers when playing 5.1 material over a 7.1 speaker system. On THX Select or THX EX systems, the product manuals state that you can force the EX mode, but the results depend on the material, and may not be desirable. On THX Ultra2 systems, the Ultra2 Cinema Mode says that it monitors the rear channels and spreads the sound around the 4 rear speakers in an appropriate manner, avoiding the problem described above. On non-THX systems, like Outlaw, or Rotel, they have Cirrus Extra Surround, or Rotel XS mode to pump the 5.1 track through the 7.1 system. I guess my question is how good are these modes? I haven't heard any of them, but I have to say, THX Select (or regular EX) sounds like a bad compromise (i.e. your brand new 7.1 system might not sound so hot on 5.1 soundtracks). THX Ultra2 appears to be a great solution (albeit rare and pricey). How do people like their THX Select/EX systems? Do they notice problems when playing 5.1 (i.e. non EX-encoded) soundtracks? How do modes like Cirrus or Rotel XS sound? Good? Adequate? Fantastic? I'd hate to spend the money upgrading my 5.1 system to 7.1 only to find that it's a waste except for when playing true encoded EX/ES soundtracks.