These springs are the same diameter and length as the factory springs on all Ohlins Road & Track coilovers for the 2008-2021 Subaru STi & WRX.
Hyperco and Swift make the best linear coilover springs in the world. These springs are extremely accurate and have very little distortion which makes them a big upgrade over the standard springs. You can also customize the rate to your liking. Many Ohlins Road & Track users find that the default rates cause a lot of understeer or ride harshly which is something that can be significantly improved with different rates and higher quality springs.
SOLD AS PAIR you will need two pairs to replace springs on all four coilovers. For different front and rear rates add product to cart twice rather than selecting quantity 2.