So you cannot take your wheels off right. Still you can see the springs clearly if you jack up the car. I don't have Eibachs but what I know is the writings usually should be readable in the upright position. I mean If you look at them they should not be upside down. Another issue is did they have them seated right in the spring buckets?

 

Make sure they're installed correctly and then get an alignment before you do anything else.

With that said, were you able to track or autocross the car to get objective data? "Feels softer" or "rolls more" don't really mean much, especially if it's just from driving around town. Sounds like you recently made a lot of changes that changed how the car feels, before you do something drastic and expensive, I would first start with making sure everything's installed correctly and get an alignment.

 

Found instructions:

http://www.partsgeek.com/assets/perf/full/1403073.pdf

PRO-KIT springs are marked with a .001, for Front and .002, for the Rear.
• PRO-KIT springs should be installed with the Eibach Logo right side up. All original stock spring isolators, dampers and tubing should be retained from the stock springs and used when installing the PRO-KIT Springs.
• After installation, it is always important to inspect and adjust the following if necessary:
- Wheel alignment such as camber, caster & toe
- Tire and/or wheel fender clearance, when aftermarket tires and wheels are used.
- Brake line clearance and attachments
- Brake anti-locking and anti-skid system sensors

Here's a pick of the rears...PROKIT..installed on an 06 (same set up):
Letters/#s are upright. Tighter coils should be ON TOP. This is also true of fronts.

]

 

All of this seems so comprehensive & spot on that I'm going to print it out & hand it to the alignment tech. Without insulting his intelligence, I'm going to ask him to go over the areas covered. Mine are like a a dark gunmetal grey 6364.140. It does need aligned & the above mentioned checked. I found the springs at Auto Anthing.com. No one could touch the 230 shipped. after I find what I want online I search for an online coupon & it knocked 30 bucks off with free shipping. Tomorrow, I'm taking it in & will write back about what was found. Thanks again for all the intelligible feedback.

 

Here is one more pick showing fronts installed and rears in the position they should be installed.

 

The shop seemed very professional. The 430 included new HPS brake pads. I let them know I had lost performance & they talked about different set ups, not that there was possibly an issue. I really wanted to plug this shop as it seemed to be an answer to a lot of 350Z owners I know. I'll know tomorrow. IT really sucks, I don't even want to drive my Z anymore. I hope this gets rectified. I've had both an SC and a cobra ruined by mechanics. I was asked to sign a disclaimer saying that even if the shop did something wrong, they were not to be held liable & that I was to understand all work was considered, "experimental". Maybe some jerk did them dirty, IDK. I'm going to hold them with high esteem until I know for sure different. They were recommended by someone I know and trust.

 

So, did you get it aligned yet? Car will drive and handle like crap when out of alignment!

 

I was going to have them do the alignment. It's PSI in Beaverton. These guys are kinda famous & I think integrity speaks to addressing this openly & professionally. We all learn, we all take chances when lowering our car. I honestly think they want me to be happy. It's bad business if I'm not. Their shop looks better than west coast customs. The owner has a GTR & the COO a 350, 370. Shops full of Lotus's, ZR1's. They're pros. Maybe we gotta a hick up or maybe I just need aligned. I'll have another set of eyes but am asking to have it gone over with me. I give everyone a fair shake. I thought 430 was a great price for Hawk pads & installing my springs. I played XBOX in their lounge that is full of big LCD's & a sound proof window to the dyno. Check out Portland Speed Industries. These guys are legit. I still never got a response back about the quoted spring rate for the Eibach Pro being softer than stock? If they are softer, there's my answer.

 

The Pro-Kit should not feel softer than stock springs. Let us know how it is after an alignment.

 

I gave you that info in post #5

 

right Ron, you said pro-296 stock 314 I think. Finding alignment place as I type.

 

They are progressive..that's the initial rate...when compressed it's 384 lbs..greater than stock. So they are stiffer overall up front. In the rear they are also progressive with a final rate close to stock for 04.05+ cars.

 

sorry i missed your post OP i've been busy with my new job and haven't been on the forum as much.

i did recommend PSI for the install. they are a world famous shop, although they do charge a little more than other places. they are highly knowledgeable so i doubt such an install was dealt with wrongly.

i'll await on further news with an alignment. good luck!

 

The Shop, Eibach & I are stumped. The car is just straight up sloppy. I've read some pretty ambiguous things about the pros. Eibach says I should be stiffer but noooo. Manufacturing is ambiguous. Many, many topics centered around, "if you track, autocross or want performance improvements, absolutely do not go with a progressive spring". Our stock springs are not progressive. My car was a beast with my fat wheels & stock susp. Eibach tech & shop are talking. Alignment's good. I'm most likely eating the investment and pulling the Eibach's & running a linear or just going back stock. Suspensions are complex. I'm adding one piece of a drastically engineered system. I could have just shifted all the work that was balanced to the front. I did tons of research & drove my car to the car failed in both configurations. Although it fails immediately with the Eibachs. Also spring rate changes in every year of the 350. A stiffer sway bar inf front will induce understeer, I already know this. I think I'm gonna cut my losses & go back to stock for the sake of responsiveness.

 

Look into the ARK drop springs

 

Sub

 

any updates OP? i hope you resolved your problem.

 

I would assume this is the rear bushings. Pretty easy to destroy if the installer is not too careful. You can look right above your diff and see if your center is cracked.

 

a couple months late, but i hope you resolved this issue. what ended up happening and did the car drive better after an alignment?