Thinking my springs were shot, I bought an Eibach Pro Kit and installed all four springs. I installed new bushings and ball joints into the control arms while I was at it.

The car now sits even lower in the front (arguably too low) and possibly higher than before in the back. In my haste, I forgot to measure the corners before the swap, but the left side is still 1/2" or so lower than the right side - I fixed nothing!

While the car was on the alignment rack, I measured the distance from the bottom of the control arm (the lowest part of the spring pocket) to the rack and found that the left side was 1/4 lower than the right. This makes me think that the left control arm may be bent. If the end at the ball joint is bent upward, this has the effect of lowering the car. And 1/4" at the spring would amount to about 1/2" at the wheel.

Does this sound reasonable? Can anyone offer any other possible explanations / solutions to my tilt-to-the-left problem? I've only noticed this within the last several months.

I'm considering a few things:
1) Reinstalling my stock springs. They checked out at the same height after removal and I was perfectly happy with the height before.
2) Shimming the left spring 1/4" (don't know how, yet)
3) Replacing the left control arm

The Eibach springs are a work of art. They are truly beautiful and look to be quality pieces. But they may not be right for me and could soon be for sale - very slightly used.

By control arm do you mean front A-arm?

In ref to your measurements:
Did ya check tire press before measuring?
Are you sure the front tires and wheels are exactly the same?
(brand, size,etc)
Spindle bent?

Yes. The front lower (there's only one) "A-arm".

The pressure's fine. The wheels and tires are all the same (stock IROC). If the spindle was bent that much, I would have some other serious problems like malfunctioning brakes and obviously screwed up alignment.

Bent a-arm is a possibility given all springs were properly indexed. But I'd like to know the distance from, say, the a-arm pivot bolts to the rack/ground to see if the spring pocket measurement is being effected by body roll/lean created by a possible bind in the rear suspension (yep, it'll throw the front way off)... maybe an lca bushing? I've heard of BJs not being fully pressed in but a 1/4" is alot more than that would be. Another thought was a stuck bushing on one side (my problem) but you have replaced those. So that leaves the rear, how does it look?

I pulled out my shop manual last night and found some interesting stuff. There are some tables containing measurements that I need to check. Various heights such as front control arm pivot bolt, rocker heights (front and rear), distance between rear axle and bumpstop, and height difference between ball joint and pivot bolt.

I realize that some of the dimensions should be off because I have installed "lowering" springs. But I should find side-to-side consistency, at least.

I want to check this stuff, but there's no way to get under the car if it's not on jackstands! I can't really see taking it to an alignment shop or oil change place (with a pit) just so I can take some measurements. Do you think that rolling it up onto some flat and level ramps would serve the purpose?

Sounds like we're headed in the right direction now. Yes I think some level ramps will do. You'd probably want all tires on ramps or boards. Maybe the front on ramps then jack up the back and put stands under axle tubes trying to keep the car level as possible so weight distribution is normal. I have used a couple of peices of 4x4 or 6x6 wood post laid down side by side under the tires. The consistency of measurements should still be there. Good luck.