Dawn of the Tiberium Age (DTA) is a stand-alone mod that combines Tiberian Dawn (C&C 95) and Red Alert. While classic mode gets as close to the original game-play and balance as possible, Enhanced mode provides improved game balance and a lot of fun new stuff. DTA features many customization options for Skirmish and multiplayer (where you can play as GDI, Nod, Allies and Soviet on over 100 maps), challenging original singleplayer missions, as well as co-op missions. Since this is a stand-alone mod, you don't require anything but the mod itself to be able to play: the original game is not required.
The build speed bonus given by multiple factories used to work very strangely with the Tiberian Sun engine. Building a second factory gave a very small boost of 10%, while getting a third factory then suddenly doubled your build speed. This obviously made getting a second factory useless unless you were also planning on getting a third factory later.
With the latest update dkeeton of CnCNet copied RA2's code for the multiple factory bonus, giving us more control over how the bonus works. Every extra factory now gives a cumulative build speed increase of 33%.