I have a few questions about the speedometer (/sm 1)

1. In multiplayer is there any way to show yours instead of your opponents
2.Im using Maya text and in single player the bottom bar turns Cobra for one frame (uke's text color)?
3.Is the top bar your top speed?

Other than those questions I know as much as I need about the speedometer

The top number is the highest speed you or your opponent managed to get.
The lower number is the speed of the player that currently has the highest speed.

So 1. Only if you have the highest speed.
2. Then that probably means that uke has the highest current speed or the same speed as you in the first frame.
3. Answered in the first paragraph.

What does it mean when the numbers get bold?

As far as I know, the speedometer numbers never get bold, and I have used them plenty of times with different usertexts.

That may just be an optical illusion of some sort.