I have a MCW '66 too, and everything mentioned in this post is true. I am going to combine mine with either a Revell '65, or '66 Impala SS, as a Maryland State Police '66 Biscayne.
I did this MCW '65 a few years back.
I recontoured the rear window, and re-did the tulip panel to a more correct shape.
I used the Monogram (Revell) 1965 Impala for the chassis and other parts, as well as the Model Car Garage Photoetch Set for the 1965 Impala, which includes "Biscayne" scripts.