Which Transmission? What Differential?

There are two main gearsets with the DCT boxes. These effectively boil down to the short ratio boxes and the long ratio boxes. Both come in a V8 bolt pattern or the I6 bolt pattern. Determining which transmission and rear differential ratio is right for you depends on the intended usage of the car. 

Check out SLG's website for some detailed information:

https://www.seemslegitgarage.com/post/dct-bibl