The effect of life fibers is rather...varried and depends on the person and what the outfit was made for. The most basic effect it has is 'increase of ability'.
A 1 star uniform ( containing only 10 percent life fiber ) appears as a normal uniform, and makes the wearer super humanly fast and strong and such. Like of wearing a suit that turns you into captain america. 1 star uniforms always look like a normal school uniform at all times. 

 2 star uniforms ( 20 percent life fiber ) are more tailored to the users skill set and can have more unique abilities. For the sake For example; the boxing club leader uniform looked like an outlandish boxing outfit, where one glove allowed him to do super human power punches and the other a seemingly endless flurry of weaker punches. But it is not limited to physical abilities of the user themselves only, as we see the gardening club's leader was able to grow super death plants. Pick a hobby/club and think about what a 'uniform' would be like for them. While we never see these uniforms outside of there 'battle appearance' in the show, for this game I am going to allow 2 star players to have a proper transformation from normal to battle mode.

3 star uniforms ( 30 percent life fiber ) deferentially transform and have the greatest increase in power and the most ability. We only see a handful of 3 star students in the show, so the true limits of their power are hard to say. Some even come with multiple forms, for example one 3 star student had a form that was entirely defensive, and one that was entirely offensive. 

So while what Tatsua did was a st-reach ( especially for someone of 2 star status. That wide a range of abilities seems much more fitting 3 star but i'll talk to them about that later ) it is a fair example of what could be possible depending on your club and how you want to play them.