If you are curious what is actually Dragonball Kai, it is actually the shorten version of the original manga where they removed away the parts that is dragging and go into the main story of Dragonball straight away.
Don't worry whether it will cause you to lose the super actions fighting as those are the main story line that they did not leave out. They only cut away those boring scene where it does not matter to the main story line.
Do check it out if you are a true Dragonball lover like me and you will definitely love it too. You can also read this following report that told you the detail of the anime, Dragonball Kai.