Players may be much more specific in how they apply their tech levels during production and the upgrading of ships.
You may choose to upgrade a group of ships to a specific tech level. Upgrades in standard galaxy would try to raise the tech level of a group to the current racial maximums. This game allows you to raise the tech level of a group to a specific level. This will enable you, for example, to increase drive tech without raising weapon tech on a group.
Probably the biggest benefit will be seen in production. You are now able to build ships at specific tech levels. This actually makes these ships cheaper to produce, therefore your planets' production is more efficient in making these ships (ie. you will get more of them). A formula similar to the one used for calculating upgrade costs is used to determine how much to discount the cost of developing a lower tech ship.
BTW: The error Galaxy 3.52 has in producing multi-turns ships is
NOT duplicated in this game. So, importing MAT only for the
last turn of production won't do you nearly as much good.