This is an excellent tutorial, and perhaps one of the best I've seen anywhere! I came out of it with SO much more than I came into it with. I didn't exactly build the Spitfire (I was working on some more "cartoony" planes), but everything in this tutorial applies!

As for your progress, so far it's looking just like the tutorial version, so keep it up. One bit of advice...have patience! It's a LONG tutorial, and there are a lot of tedious (though useful) procedures which will need to be performed before the plane looks like the finished version. UV mapping is one of those, but this tutorial is how I learned UV mapping!

Have fun with this, and remember the techniques can be applied to pretty much anything else!