TRD springs, RSB and FSB can all be bought at any dealer. You can also look on line as many dealers sell there too. You can find Eibach springs many places too and I think they are the perfect springs for the Corolla. Ultra Racing suspension pieces and chassis braces are available too. Just doing some on line hunting! Here are some pics of my 10th Gen Corolla S Turbo with some of the suspension upgrades. Many oof these parts fit the 10th and 11th Gen Corollas.
TRD Front Strut Brace
Ultra Racing Rear Upper Strut Brace
From back to front of car.
1. Red TRD RSB
2. White Ultra Racing 19mm RSB
3. White UR 2-point rear lower chassis brace
4. White UR side chassis braces
Red UR lower front 3-point chassis brace