Here is where all of Rei's transformations into Sailor Mars will be listed in chronological order.

Mars Power, Make-Up!

This is Rei's first transformation. It had it's debut in episide 10 or 13(I think, can't remember)

Mars Star Power, Make-Up!

This is Rei's second transformation and firts appears in Sailor MoonR during episode 63.

Mars Crystal Power, Make-Up!

In the anime this is Rei's last transformation. It transforms her into Super Sailor Mars and is first seen during the Sailor Moon SuperS series in episode 152

* In the manga she gets one more transformation to turn her into Eternal Sailor Mars, but I'm not sure what it is.

Mars Planet Power, Make up!

This transformation is in the manga only and is similiar to that of the outer senshi.