I have an RCA HTIB 650 watt system....I did not have a ton of cash for a Bose or higher end system , but this system has really worked well for me, I have really enjoyed it. My question, though, is if it is possible to buy another sub and replace it with the sub that came with my HTIB. The RCA sub i have now works fine, but I have noticed that a friend of mine has a 400 watt Sony system, and his sub is ten times more effective than mine is. His even has a sub volume button on it, and as far as I know, mine does not. I was wondering if there was a setting or a way to increase the bass, or if my sub is just too much on the lower end and I need to replace it with a better sub. Which subs do you recommend, and is it even possible to hook up a different sub other than an RCA if the receiver and all the speakers are RCA?? Would a higher watt sub burn out the receiver if it is too powerful?? Thanks for any advice.