I'd get a seperate stereo pre, and a seperate stereo power amp.

and most likely seperate stereo speakers, and if money is no object, I would place them in a seperate room, with seperate dedicated power lines...

surround pre's have a processor to do effects & stuff, you don't need them in a stereo pre, so signal routes will be much shorter and cleaner in the stereo pre and poweramp. Thereby the stereo pre will sound better.

Keep them spinning,
Bert.