Thanks Lowell: I know 4.5 is an in-place update of 4.0 versus side-by-side like 2.0 or 3.5. I'm not so much worried about Visual Studio as much as issues "hosting" SSRS, etc. I know in 2008R2, we aren't using IIS as the back-end for SSRS, but to complete the analogy, IIS has different app pools for 2.0 vs 4.0 framework. I was worried that by updating 4.0 framework, something on the report serving side might inadvertently reset.
At any rate, I'm going to give it a shot. Thanks.