I have a 03 Altima. I lowered the front a inch and a half and left the back stock. To me it looks great the way that it is, so I dont want to lower the back at all. I am selling some springs for the back only that will lower it a inch and a half.
I believe its M2. They got ordered from Ebay, I love having the front ones on. Riding in the car you cant really tell that its lowered the ride is almost just like factory.