1. I made a litle intro with fade in and out, but if i render the intro it only starts playing after the fade in and ends before the fade out, how to fix this? (the music starts to after the fade in etc.)
As Gilles said, make sure when you render that Render loop region only is NOT checked. This will limit your render to only the loop region if checked.
2.I got a song on it, but the video is not so large as the song, so there is some music left (i want it like that) now in the preview it plays it perfectly, but if the file is rendered, it plays only the music till the video ends, so there is no music left. Any ideas?
I agree with Gilles this may be because you are only rendering the loop region and it is set to just the video.
3. How to make a title change colors when video plays?
You can keyframe color changes on the Properties tab of the Text Media Generator. There is a small timeline at the bottom of the Media Generator window. If you move the little timeline cursor indicator you can change the text color and it will make a new keyframe indicated by the small diamond. You can right-click those keyframes and set them to Hold if you want the changes to be abrupt. Otherwise they will change over time.
Like this:

~jr
http://www.johnrofrano.com
http://www.vasst.com