The Maelstrom Mod introduces four new races to the Sins of a Solar Empire Rebellion Universe. They are independent of the original races and have unique strengths and weaknesses. Maelstrom is available for Rebellion, Diplomacy, Entrenchment and Original Sins.
Standard Series - the Maelstrom Mod introduces three new races to the SoaSE Universe. The TEC, Advent & Vasari are still found building and battling as usual. The new races are independent of the original races & have unique strengths & weaknesses.
is this the complete update where you can build titan ships?
The differences between the two versions are explained in the section "Versions of Maelstrom" at the top of the summary page.
The quick answer is no, you want the Expansion version.