Are you trying to talk yourself out of the SVS? Seems like a perfect choice for your situation. I started with the PC2000 Ultra, then bought a SB4000, then a SB3000. Each integrated easily by themselves and now I use all three. Hard to beat. Good luck. Once you get a sub dialed in the first thing you will ask yourself will be, why did I wait so long.
Replacing current sub with another
I am in the process in replacing my current sub with something with better control, meaning tuning and integrating. My option would been a SVS SB-1000 pro. Keep in mind I have a very small room and really the Vandersteen 2ci are more then enough for the need of any music. I have a sub not for output but for quality and and response. I have the tools to tune and integrate the sub with the 2ci so that is not a factor. I currently have the HSU STF-2 and is a great sub but it only has the basic controls so I am limited.