This expansion is awesome, especially for a lower price than retail. Kind of hard to put pieces together, but its well worth it! (If you are struggling to piece it together, take a cup of water and put it in the microwave until it is close to boiling. Then stick the ends of the pieces in the water for maybe 30 seconds, wipe them off, then shove them where they need to go. It softens the plastic and helps it mold better. And when it dries, it hardens in place!)
The model itself is beautifully crafted, but getting this thing together was a royal pain. I ended up taking a nail file to the attachable components and filing them down just a bit and voila they fit perfectly.
Otherwise great, and worth the price.