Speed is a interesting concept and a top speed is a really weird way to state it.
We ran swerve this year using something almost identical to what 1640 uses. We ran something at like 12.5-13.5 fps single speed. Acceleration matters much more when you are supper maneuverable in a tight space then when you just want to out run your competition. We wanted something just above the median speed range but not so fast that we would never reach the speed. So a acceleration that we can reach top speed in about 3ish robot lengths. The key is not to be to fast to out run your opponent nor to slow only be where you need to be in such a way that it would appear effortless.
https://www.youtube.com/watch?v=Lpb2...DIBcQ&index=37
Us team 2517 were always where we needed to be to play defense in just the right time in such a way that it would be hard to see where we were going.
Now there is some cool things you can do with swerve that make it appear that you are travailing much slower then you really are. By making small circles where a normal tank drive would drive back then ram you can be essential ramming at full speed even though it takes up the same amount of space as a tank drive would take to break and start moving again.