I cut my Eibach springs

that would be a possibility, i have my eibach rear sway bar on the stiffest setting, and it still made my car feel like it wa understeering (mainly in slippery conditions). a full hotchkis set for the cts or cts-v version would make the car tend to understeer even more, judging by front to back ratio of thickness. a thicker rear fom hotchkis and an eibach front might do the trick, but i don't want too rigid of sway bars, considering my shocks and springs are rigid, and i have strut tower braces rear and back. from what i understand is, if you have softer suspension then you would want beefier sway bars, but if you have stiff springs and shocks then you don't want your sways as thick. i ended up choosing eibach because it had a better front to rear ratio for less understeer than bith of the hotchkis versions, and because of my stiff suspension already, i could get away with not going with the thickest sways available.
anyway i wanted to trim my rear springs anyway for looks, and it helped with handling too. i researched much on the subject and asked around quite abit before deciding to cut them.
i know my bling is blinding, i actually have been contemplating taking them off, but all my friends say leave them on. i just think they are one of those things that look better in person(on a silver car of course).

This is what I did to mod my fe4's, I did the same thing with my fe3's with a modable top mount to get the full eibach drop. I figure this could be done to achieve about as low as you would want, by cutting springs and modding the rear self leveling shocks. I borrowed some pics from whldwhl, seeing as it's his spacer mod but taken even further.
Just as a note fe4's top mount sits 1/4" lower than the fe3"s.

I disassembled the shock, and discarded the rubber piece below the top mount and above the dust boot, this will get your shock 1" lower.
*See cadillac faq's for the whole mod.
http://www.cadillacfaq.com/faq/answers/lowercts/index.html

To get the full eibach drop or if you want to lower further by cutting springs you need to lower the top mount further than the spacer mod allows for.
The steel plate on top of the dust boot rests on a ledge on the shock shaft, this controls where the top mount sits. To get the top mount lower I ground a new ledge on the shaft for the steel plate to sit on.

Grinding the shaft is surprisingly easy, the metal is fairly soft. I measured how much I wanted it lower, in my case it was 1/2". I marked it with a marker. Then ground it with a bench grinder and dremel being carefull not grind it more than my mark and not grind deeper than the thin part of the shaft. Really it only took me like 5 minutes.

I finnished off the new ledge with a flat file making sure it was even. It doesn't have to be machine shop precise, just even enough that the steel plate sits flat.

Next I removed the steel plate from the dust boot to get the bump stop out. I tapped a screw driver betwwen the dust boot and steel plate so I could get the driver above the dust boot and pry them apart. Once they are seperated the bump stop will just fall out.

So the shock doesn't bottom out constantly on the bump stop I trimmed it the same amount that I ground down the shaft (1/2").

To get them back together a baseball bat works perfect, I put the plate on the floor, then put the dust boot on and pressed it back together, then I did the same with the bump stop.

Then i put it all back together, I installed 2" rubber and steel washers to make up for the rubber I removed and for the material I removed from the shaft, so the washers added up to about 1 1/2". I alternated 2 rubber and 1 steel until 1 1/2" was achieved.