I have to decide between the 510 and the 320. I don't really need 7.1, and my current speakers are only rated to 75 watts. I listen more to music and when I do HT it will not be at high, high volume. I can get the 310 and 220 also, but thought the extra watts would be a nice change. Between the 310 and the 320- is 7.1 the only real difference? Can I upgrade the 320 like I can the 510? Or should I simply save some buck and get the 220(PLII?) and upgrade to seperates for music when I can afford it- which may be never. (Paul if you are reading this and emailed me, I'm posting because I can't get to my e mail right now as I am away from home). Thanks to all in advance for the advice. Jose PS- My HK will be in an armoire and I was told they run hot- will this be a problem? It will be on it's own shelf with space above and in the rear.