The Shotokankatas contain a plenty of very important elements which one needs to practice according to his/her personal level of training.
Taikyoku Nidan is the same as Taikyoku Shodan except that all the punches are performed at high (chin) level and in Taikyoku Sandan all the blocks change from down block in front stance to middle inside-outside block in back stance with all punches at high level.
The standard Shotokan form lacks the last four techniques that are found in the Shorin Ryu version.