In Twilight of the Arnor, Technologies are quite different depending on race or custom technology tree. Each race has a different Tech Tree. You can also create your own. All Tech Trees are significantly different and geared towards the race that they belong to. For example, the Drengin Tech Tree replaces Xeno Engineering with Xeno Slavery. They also have Slave Pits instead of Factories. Each race also has a number of special techs that are unique to that race's Tech Tree and cannot be researched by other Civs. (They can be traded to other Civs.) Each one of these "Special" Techs carries bonuses. However, as each race has them they balance out.