To a team without any experience making a servo shifter, it would seems impossible to do without a machine shop. However, many have learned that it take mearly a hand drill and a couple pieces of metal to make a successful one. All it take is simply looking at other's design, and trying to duplicate it.
Given a week of time, ANY team can make one work as long as they've seen it before.
If you want to hear what people have to say about shifting gears on drive train, take a look at this thread:
http://www.chiefdelphi.com/forums/sh...threadid=16810
Having a speed shifter on your robot simply give you more freedom in the match. It is true that you may choose one speed during one match, but over all, there will be many different situations, and you may find yourself needing more torque, or more speed depending on what teams you are playing with. All it take is a few pounds, and a few days of work, with many things to gain.