Hi guys, I had a question about upgrading, and whether or not it's worth it for me. Right now, I have Klipsch RF-3 mains, an RF-3 center, RS-3 surrounds, and an SVS 20-39PC sub. I'm using a Denon AVR-3801 as an amp and a preamp. Clearly, these are not the world's best components, and upgrading some of them might be worth it, in most circumstances. However, my audio source is all mp3 audio from my computer, for which I have a sound card that outputs the signal optically to the receiver. Now, given that I'm not using the best sound source, will upgrading my speakers/amp/preamp make a difference in audio quality for me? I don't think I'm willing to give up the convenience and low price of the audio format. Given that, would it be worth upgrading my system components, or is my audio source going to be such a bottleneck that I won't appreciate the benefits?