ideally the best way is to measure the distance from the center of your wheel's center cap to the highest point of the fender arch. some cars run different tire sizes that offsets ride height if you just measured from the ground to the fender arch.
how about you take a flash light and peek into the wheel wells? if the springs are green they are teins, black probably eibachs, and so on.
see if you can see the part numbers printed on the springs and just search online.