Problem with Eibach springs on 993TT

[snowmanmtl]

Just put the Eibachs back on ( removed them after a year on bad roads) and the car is all over the place at speed. It's very scary at anthing near 100mph on the highway. Feels like you're being hit by a sudden gust of wind or following a groove in the road, twitchy, and very unstable.
The first time I put them on it did the same thing but, at the same time, I changed the rear tires to S02 s while keeping the Pzeros up front. I assumed the tires were to blame. Both times an alignment was done after the springs were installed. The car is solid as a rock with stock springs. Is this a problem with the shocks?
I plan on using the car mainly for DE events so, I put the lower springs back. Any input would be greatly appreciated.

[maxnine11]

the original shocks are of marginal quality; with a very short life span. they also do not work well together with lowering springs. the eibachs are one of the softer spring options.(you do have the turbo spring set, right??) I have read a lot of complaints about H&R and Eibach springs not working well with stock, worn shocks. I have also read that used Eibachs will continue to sag with time and use.
i have Bilstein HD shocks/struts with Eibach springs on my 993 (non-turbo), and am quite happy with the handling and ride height. if i were to do DE events, i would probably have gone with a slightly stiffer spring, like the Porsche row M030 springs.
you could go the Bilstein PSS-9 route, and cure the spring and shock/strut dilemma in one go.
these cars are VERY touchy to alignment settings. If the tech doing the alignment isn't top notch, it will show up!!
max

[snowmanmtl]

from your answer, I must assume that my shocks are history!
I had the springs ( Eibach Pro kit # 7209.140, which are correct for the Turbo, you scared me there for a second) installed 06/2000 and then had the P dealer do the alignment. Removed them a year later. Just had them reinstalled and had alignment done by an independent garage. Same results both times. I don't think the Eibach can be tired after just one year on the car so I'm shopping for a set of Bilsteins.
Did some browsing and found this note at Tweeks under 964 bilsteins ( they don't seem to have a listing for 993):

"Note - If Bilstein shocks are used in conjunction with shorter aftermarket springs, the shocks selected should be Sport type. HD type shocks are not suitable."

Does this relate to 993?
At this bilsteinshock site they also make the same note for the 993. As well , the PSS9 upgrade is only $ 500 more then just the shock package. Is it worth it?
http://www.bilsteinshocks.com/bilstein/html/show_shocks.asp?make='PORSCHE'&model='911%20Carrera,%20911%20Carrera%204,%20911%2 0Turbo%20Carrera'&year='1997'

Thanks again
Mike