I'm not sure what vCAT part you are referring to.
If you aren't using resource pools as providers, then a provider directly maps to a cluster in vCenter.
The Speed/Memory performance is guaranteed at the VM level by what type and configuration in an Org vDC.
you can present multiple storage policies/profiles to a single provider (many people do this).
then only allow a specific policy to an Org vDC where a VM might exist.