I finally sold my RD spring at a not so bad loss, so I am looking at the CSI springs, how much of a drop do they give you?

Also I know they are the stiffest springs they make for the e31, anyone here have any experience with them, pro's and con's

They are not the stiffest. The stiffest front is the Eibach. The stiffest rear is the Dinan S2/3.

Thanks for the education, so eibach are they still made? I know the Dinans are prob not available at all

Google is your friend Rob (http://www.sears.com/shc/s/p_10153_12605_02855195000P?vName=Automotive&cName=Suspension&sName=Performance%20Enhancements&psid=FROOGLE01&sid=IDx20070921x00003a) lol

Eibach rear springs are just cut OEM springs. They are a very poor match relative to the stiff front (but great for H&R front spring people!). For the rear you will want to use CSi springs or Dinan springs for proper F/R balance. Anything else tends to far to much understeer.

JFR, H&R fronts are not that soft, they are the same rate as the OE Mtech front springs...just with more drop!

is there are reliable store or online place that someone would recommend that sells the eibach springs?

Eibach rears are not cut stocks, They may be similar in spring rate when cut but not the same.

Ok if you want to be really technical, they duplicate cut OEM, with the same coil length, diameter, etc.

Geez people..... springs specs have been beat to death! Does noone read the info that MWrench has so graciously and painstakingly provided or search the archives here? It took about 10 seconds to find the answer to the OPs original two questions. May not be the cheapest but you don't get much more reliable than Sears....

I run Eibach pro springs on my 850, 20/15mm drop.
I don't think the rears are soft at all.
With the Bilstein shocks the ride is pretty firm, cobblestones and bumpy roads are very uncomfortable.
But I have been able to corner at "lightspeed".

Worth mentioning that the Eibachs does not drop quite as much as the claim though

In Addenum (sp?), Ed has recently updated said data with the Euro Mtech spring data for the rears. Great work as always.

I run Eibach pro springs on my 850, 20/15mm drop.
I don't think the rears are soft at all.
With the Bilstein shocks the ride is pretty firm, cobblestones and bumpy roads are very uncomfortable.
But I have been able to corner at "lightspeed".

Worth mentioning that the Eibachs does not drop quite as much as the claim thoughThe data is measured and published.
Your masking the effect to a degree due to your shocks.

In Addenum (sp?), Ed has recently updated said data with the Euro Mtech spring data for the rears. Great work as always.

The data is measured and published.
Your masking the effect to a degree due to your shocks.

I was thinking the same thing.

Anyway, if the ride was any harder than it is, it would just be plain uncomfortable.

It would be interesting to know Noggie if you had the same opinion of the ride quality if those Bilsteins were valved for the 'comfort' setting. They only offer the 'sport' setting publicly now, but you can have them revalved to the other that used to also be marketed. That comfort setting is still more firm than stock.

It would be interesting to know Noggie if you had the same opinion of the ride quality if those Bilsteins were valved for the 'comfort' setting. They only offer the 'sport' setting publicly now, but you can have them revalved to the other that used to also be marketed. That comfort setting is still more firm than stock.

This is a lot of "what if mabye".
I like the ride as it is, and it is much firmer than stock.
I don't feel that the reas is soft, and with the caberplates and the stiffness of the suspension this car corners really well for a 2 ton chunk of metal.
Not quite at par with the M3, but alot more fun than it used to be.

I think the Eibach/Bilstein is a very good combination.

.
With the Bilstein shocks the ride is pretty firm, cobblestones and bumpy roads are very uncomfortable

And you like that? This is not the first time I've heard that about stock Bilsteins and of course they are much firmer than stock. I would rather have a better blend of ride comfort with a performance upgrade (cornering). Will it be much different? I won't know till I do it. Based on real world statements of owners like you I will have the rear shocks valved to a softer setting.