I think you might want to start a new thread and ask this. Are you looking to go 80 mph? I don't think you are going to get there uless you buy a Shumacher....I forget which one, and regear it. There really aren't too many guys who go that fast, speed is only a part of this hobby.
I would love to get a shumacher, but the parts supports is not that great where I am at. I saw a video of one that was running at 60mph, ran into a wheel of a real car and just disintegrated.
You could get an RTR take a picture of it, take it apart a little bit. Take a picture. Take it apart a little more, take a picture until its all taken apart. Show the pictures in backwards order and no one will ever know you got an rtr.
NTC3 has a lot of aftermarket parts, good spare part support and is a great price. I would go with the RTR for your project and because you are going to stay in the hobby, after the project, hop it up like mad and make it as fast as you could afford.
Just my 1cent because my opinion is not worth much.