This really depends on which version of VSM you intend to move to. The most recent support hardware list is available here:
http://www.cisco.com/c/en/us/td/docs/security/physical_security/video_surveillance/network/vsm/release_notes/7_6_0/vsm_rn_7_6_0.html#pgfId-63056
HTH. Cheers!
Scott Olsen
Solutions Specialist
Bulletproof Solutions Inc.
Web: www.bulletproofsi.com