Audio Postproduction Help with Tempo and Sync in Sonar X3e

Hello! I am working in the audio postproduction of a movie and this is my first time working in Sonar 3Xe. I load the video and go to clock and I put the time code so it can sync with the video. My question is ¿if I change the Tempo will I loose sync in my dialogs and other fxs? ¿will the tempo changes alter the pitch of my sounds? ¿In what tempo should I work on?
It’s my first job and I don’t want to screw it up
 
Thank you for your help!!

It's possible to lose sync if the tempo changes in the default set up, but if you
1) CTRL-A to select all your clip,
2) Click on the "Clips" Tab in the Inspector,
3) choose "Absolute" for the "Time Base" ("musical" is the default),
the clips won't move if the tempo changes. Each individual clip can be either musical or Absolute, so if you need them to follow the tempo, they can.
If I'm not scoring, I generally leave the tempo at the default: but if you are using tempo-based effects, it is simple to do so. Note that whenever you insert/ record/ create a new clip, the Time Base will be "musical" so it will move if you change the tempo before the clip. 

Thank You OscarLaun!
¿So in my case that a don’t do scores I will always have to change the Time Base to Absolute? And simply let the tempo alone and don’t fiddle with it.
 
Thank you guys very very much, you are a life saver