Need quick help for tonight!!!

I'm DJ'ing tonight for roughly 300 people and I don't want to bring my large system, but instead my 2 smaller systems.

The system is 2 of these: http://www.b-52pro.com/products/Matrix2000.html

Essentially it is 2 powered/active subs and 4 passive speakers. Can I link the 2 from my VCI-400 to double my sound??

Yes... just plug the output of one into the input of another.

TRS to XLR Male from your VCI to each sub.

Then XLR-XLR from the Full-Range-Output on the side you connected the VCI, to the remaining input on the sub.