Is bass response the major shortcoming here? Sounds like a bass issue, but I'm just guessing here.
If bass response is the issue, consider a decent subwoofer. The lack of bass w/the VR20s is not surprising as their frequency response is likely (and realistically) not any lower than 50Hz, if it's even that low. A solid sub w/the 20s crossed over correctly from your receiver will bring the VR20s to life. Unfortunately, I don't believe these are close to full range. Unless they're fairly capable towers (35Hz and under), you're likely to get subpar bass from them for deep music passages and typical LFE in movies.
If you to use your system 25% or more for movies, a good subwoofer is a neccessity... -TD