Home Theatre Processor reccomendation

Looking at a host of used versus new equipment and have the following decision to make. If new, looking at the Sunfire Grand Theatre 3 and the B&K Reference 50. Used components include the Cal Audio CL 2500, the Classe SSP 75 and the Krell Showcase. Assume any of these will be a tremendous upgrade to the current surround sound setup which utilizes the Adcom GSA 700 looped through a classe CP 60 pre-amp.

Any and all feedback/thoughts is much appreciated.