I saw this at elitist jerks forum, so I`m gonna link there. Theres a link at the OP to the tool itself. It seens the UI is really really friendly and easy to use. And if you are hardcore, theres quite some ways to tweak stuff. There are some minor bugs but it seens its doing quite a great job from what I can see.
http://elitistjerks.com/f73/t86901-team_robot_simulator_gear_comparison_tool/