Advice on Seperates?

I am an old Hafler fan. I have collected 7 Hafler XL-280's that produce 400 watts in mono. They will be the backbone of my dream system. I would like to begin the upgrade a piece at a time. Any suggestions on a Preamp/Processor? I currently use a Harmon Kardon AVR 80 with the seperate ADA 330P Dolby Digital Processor. I would like to add DTS and the new 6 channel (rear center) and 7 channel matrix sound in the replacement.