Distant Stars is a collection of changes that Skyline_HUN made to the game to become more enjoyable even on huge maps. He found the research tree too short for a 4x game. So the first thing the MOD does is greatly increase the research levels. Now most of the weapons, shield, armor and HP research have 6-10 levels per-technology each. Now, a technological advantage really becomes major factor in the game. Also he tried to increase the differences between the three races by research. The MOD also increases the differences between the three races by increasing the advantage the research grants.
This actually means, the Trader Emergency Coalition (TEC) have more levels for trade and defense, Advent have more research available in beam weapon technology and fighters/bombers, Vasari can now increase their phase missiles to really pass through shields and have more weaponry research. Some default researches have been tweaked to help improve the the differences between the three races.