I just got my new 400/400 spring rates. One is 7" long and the other is 8" long. I guess its my fault for not specifying that I wanted 8" for all four. But anyway, which ones should I put in front? How would a 7" spring behave compared to a 8" of the same rate?

 

Put the longer ones in the rear. They will behave the same.

 

what would be the reasons why one would get different length springs? why would GC supply with two different lengths by default?

 

you need more free length in the back of the integra. shock is mounted lower (on the control arm instead of a fork)

 

Also they came with different length sleeves. Im guessing the longer sleeve goes with the shorter spring, and the shorter sleeve with the longer spring?

 

The longer sleeve goes on the rear. This will become readily apparent when you assemble them on to the shock.

 

I have my 8" springs in front and 7" in the rear. The fronts rest just even with the upper mount but the rears have about an inch or two of free movement when the car is not on the ground. I haven't had a problem at all though with using the longer ones in front.

The perches are set just like you said though. Longer in back shorter in front.

 

You can pretty much put them anywhere with the adjustibility in the spring perch and the Koni snap ring.

But, long sleeve + long spring in the back is the general rule. I am running 8" springs front and rear with the long sleeve in the rear.