Reply to S4 or X1 ?

Hey guys,

i feel like moving forward and sell my beloved VCI-100.

I would prefer a set up that cost less than 1000$.

I was believe of buying a s4 or two x1's and a behringer DDM4000 mixer.

The s4 would be around 950$ with shipping and the other set up 1000$.

I am wondering

1. what do you believe about that
2. what soundcard do i need with the two x1 and DDM4000 mixer. Does it work with my DJ i/o?

Thanks a lot