I have a Panasonic receiver that came with a HTIB. I have since upgraded my 3 front speakers to Polk RTi6 and CSi5 & my subs to Polk PSW404. I was contemplating on upgrading my receiver to a denon 2805 or Onkyo SR702. Will I hear a noticeable improvement in sound quality if I upgrade (movies and music)? I don't really mind the extra features. I'm more particular about the sound quality and would like to know if its worth the investment. By the way, I don't have access to stores that have demo units (ie. best buy, etc...) so I can't try before I buy.