There is no official wm6 rom released from Verizon. Or sprint, altel and others for that matter.
You are most likely running wm5 aku2.2.
This is the latest official rom from Verizon. It is wm5 aku.3.3. Released about a week ago. Either rom will speed up your phone. aku2.2 was very slow and hung allot.
http://www.utstar.com/PCD/downloads/XV6700%20AKU3.zip