Really nice work! Had never driven this track before, but when it had loaded I instantly thought "this right here, is nice".
I think you can improve the surfaces a bit more (I have installed the surfaces from your edit as well), and some bumps feel a bit overdone, but that could be as it is in real life. Compared to Kunos tracks it also looks a bit dark. All of this forced me to drop one star, but if you get this right, it's very very very close to Kunos quality in my book!
Really nice to see a first mod this well done, love the smooth white lines on the corners as well :)