H&Rs: Front is dropped more than Eibachs, rear is less. H&Rs give a "raked" look (where the front seems slammed and the rear is a little higher). Ride is slightly stiffer than Eibachs.
Eibachs: Front is a little higher than H&Rs, but rear is dropped more. Eibachs give a more "level" look to the cars. Ride quality tends to be slightly more comfortable on tough roads.
Both companies are very respectable in suspension components.
Alignment is a must after lowering a car because toe will be out of specification. You can also now buy a camber/caster adjustment kit, which will allow you to change these specifications after lowering. Upgraded struts are also highly recommended because not only will they last longer than stock struts, it will save you time changing them when you change the springs, instead of having to replace them later! Good luck!
