You can have a different name is you wish but it would be easier to build the new servers and setup replication to easily move everything over. Supported methods/scenario are here:
http://www.symantec.com/docs/TECH104389
Yes, you would need to put in the drive letter you want to use. If you leave it at default (C:) it would overwrite what you have now:
http://www.symantec.com/docs/TECH102896