You don't need to set EnableViewState to False, or EnablePartialRendering as the events that create the ViewState are not called/used in ASP.NET MVC.
As for the ViewState still being set from the RadScriptManager, put this in your View and it will disappear (at least it does for me):
| public override void VerifyRenderingInServerForm(Control control)
I haven't seen a consolidated MVC performance thread, but if you look in the Telerik blogs you will find posts on how to optimize the controls in MVC. I also find that if you use JQuery instead of the standard Microsoft AJAX your page sizes (and subsequent calls) will be less, and the pages seem more performant.
If you have any other questions, I'd be glad to help.