New Post: Restart engine

So actually it is still IMPOSSIBLE for REngine to restart without restarting the whole c# project?

Yes, R.Net simply wraps the unmanaged R dlls so that you can call them from a .Net process. There are ways to push the R.Net wrapper and R out of the IIS process using WCF, .Net remoting, or even DCOM, but these techniques are not a part of R.Net.