Complex sentence: A grand finale is performed on the last day by all the competitors, except for 2006, because of the 4th competitor, the finale is shortened to 6-minute and without components from participating countries.
Split into simpler sentences: A grand finale is performed on the last day by all the competitors. The 2006 competition has been the only exception because of the addition of a 4th competitor, the finale was shortened to 6-minutes and without components from participating countries.