The CVR's are decent subs in my opinion. I lucked into a cheap pair of CVR12's on ebay back in late 2005 ($20 for the pair, lol) and they have taken a beating, one has light coil rub for the last few years, but my MTX 1501D hasn't killed them yet; or any other similar amps over the years. Honestly they have decent output and can sound pretty nice overall in a good build, not "extreme" subs, but capable of really good performance.
Just use what you have and have fun with it!
I'd power them with more than a kx400.1 though.