I have Kenwood KC-X1 preamplifier that has outputs for 5.1 surround including for a subwoofer output. It is hard to find preamps with internal surround.

I think it is how you like it, powered or integrated doesn't make any difference.

I have powered and integrated amps all sound good. When the amp it is powered you have many more options to add equalizers and to run everything through the EQ.