Can I run 2 subwoofer amps for 3 DVC subs?

Need some help/input on my current setup and what I'm thinking.  

Here's what I've been running:  Xtant X1001 Mono Amp pushing
                               3 10" 4 ohm DVC subs in Parallel/Parallel
                               Amp is 1 and 2 ohm stable.  1000watts
                               Subs are 500 RMS, sealed .63 cuft box.
I have been wanting to upgrade my subs to JL Audio 10" W3V3  Looking at my setup I'm starting to think that maybe I've been underpowering my subs.  

Now I'm thinking about adding a JL Audio 500/1 amp to run one sub and leave two subs on the current Xtant amp.  What are your thoughts on that?  Would that be ok to do?  That would give me 500 RMS watts to each sub.  One sub for the JL 500/1 amp and 2 subs for the Xtant 1000/1 amp.  And do you think I'd get an improvement in performance?

And, do you guys think I'd see an improvement in performance if I changed out my Xtant subs to JL Audio W3V3 subs?  I would use the exact same sealed boxes.  Each sub has it's own sealed box.

And lastly, what are your guys' thoughts on the Xtant x1000 amp and X1044 subs?  I was told that the X1000 amp was a TRUE 1000 watt amp.  I've been running my current setup for about 4 years now with great success but always wanted more and cleaner bass.  Would adding a JL audio amp give me that by spreading the load for the subs over two amps?  Or would going with JL Audio W3's give me a big performance difference?

Thanks for ALL your help guys!!