Project MK3 and Project IC125

Ok you guys, I am starting my first customization project. I am converting two of my older trackmaster cars to british Mk3 passenger cars.
Here's a link to wikipedia:
http://en.wikipedia.org/wiki/British_Rail_Mark_3

I am also converting an old east I front car into an intercity 125. Here is a wikipedia link:
http://en.wikipedia.org/wiki/InterCity_125