Eibach's are about as good as it gets. The wire used to wind the spiring is often a smaller diameter than other makes for the same poundage, which reduces the risk of going coilbound. Eibach springs are manufactured to very tight tolerances, and generally speaking, they are usually within a couple of pounds of the rate stated, wheras on other springs you can experience a difference of 3% or more as an avarage. With Eibach's you will find that the first coil is ground flush with the second coil which allows the spring to sit correctly in the spring seat.