You want a torque pipe. Short and fat. Like the Traxxas pipes. Here read this review Harryball did for us on the difference between torque and RPM pipes.

[link=http://allaboutfunhobbies.com/pipevspipereview.htm]http://allaboutfunhobbies.com/pipevspipereview.htm[/link]

But for more take off you would want a torque pipe.