CHoosing the right Symantec backup product

Hi - we currently use Backup Exec 2010R3 which writes data to tapes using full & incremental backups on a 4 week retention period. The data is files, folders & exchange logs. We are going to start backing up our data to an offsite location, and I would like to move to a snapshot based system where I can perform one initial full backup (around 3TB) and then only ever backup the changes in future. In a traditional full/incremental system I'm not sure this would scale, so I was wondering if backup exec is the correct product for this requirement, or if there is another Symantec non-cloud based product that would work better (as the data needs to be in our data centres)?

Thanks