I've heard about chassis reinforement, but not too familiar about the specifics, how does that work? How hard is it do? How much does it run for if I were to get it done from a shop or something?

I have an S4 T2.

 

Usually most people just have a cage installed. Not just a hoop or anything, several point cage connecting to all shock towers, front and rear. Very very expensive... You can also weld in beams connecting the subframes etc...

 

It's mostly agreed reinforcement for high torque isn't necessary until ~450ft-lbs or more. Now stiffening through a cage, x-brace, roll bar, etc.. will help somewhat in cornering.