As far as I can see, you integrated some HD-Elements from the SE, like one of the poles in the background, etc.
That's a lot of effort, but I believe it can come off, looking a bit odd... because one sees the picture as a whole, and when certain elements have more definition, it makes the background (like the building) appear even more blurry...
And also the perfect clean up of the old picture is dangerous, since it can take all life out.
For a movie I did, were I had to uprez certain shots I experimented with grain, and it works quite well for the eye.. in this example, if you try to integrate an SD shot into an HD film.. and this shot is very clean, you could put a little bit grain on it, but in HD.. so the grain parts and their movement will be very small and work in 1920x1080 and make the picture appear more detailed than it really is.
But an effect like that will get lost on youtube, since the compression cleans it up again. But for a Blu-Ray file it could work..
So my personal feeling is: rather take the whole shot in SD, and rezise it, maybe with a little bit grain in HD, before putting in single HD elements, that stand out.
But maybe others see it differently?