A. RSAT is the management tools you get with Windows Server 2008 R2. Some of the tools are updated for Server 2008 R2 to support new features, such as dynamic memory and RemoteFX. To update the tools, install the RSAT tools then apply SP1 to the Windows 7 box. RSAT will be updated with the SP1 tools. As can you can see here, I'm running the SP1 version of Hyper-V Manager (you can see dynamic memory).
When the SP releases I'm sure we'll see an updated RSAT that includes the SP1 versions of the tools.