Does inverting the "if' improve performance?

I've been using ReSharper for a while now and sometimes it suggests that I invert the if . I guess an example would be a better explanation of my situation:

Access to Modified Closure

string [] files = new string[2];

    files[0] = "ThinkFarAhead.Example.Settings.Configuration_Local.xml";

    files[1] = "ThinkFarAhead.Example.Settings.Configuration_Global.xml";



    //Resharper complains this is an "access to modified closure"

    for (int i = 0; i < files.Length; i++ )

    {

        // Resharper disable AccessToModifiedClosure

        if(Array.Exists(Assembly.GetExecutingAssembly().GetManifestResourceNames(),

        delegate(string name) { return name.Equals(files[i]); }))

             return Assembly.GetExecutingAssembly().GetManifestResourceStream(files[i]);

        // ReSharper restore AccessToModifiedClosure

    }

Virtual member call in a constructor

I'm getting a warning from ReSharper about a call to a virtual member from my objects constructor. Why would this be something not to do?