These are parts for the 1993-2001 (GC chassis) Subaru Impreza/WRX that are primarily suitable for TRACK/COMPETITION use. That's not to say you can't use these on a street car, but these parts are designed for maximum precision and positive locating of the suspension at the expense of all other variables, which means significantly higher levels of noise/vibration/harshness (NVH) and potentially shorter lifespan than traditional rubber bushed street suspension parts.
Coilovers in this category are going to have the highest spring rates, the most adjustment options, and the least amount of squishy rubber.
If you are chasing that last 1/10th of a second off the lap time at your local track, these are your parts.