You having problems with the Fortunes? They crossed my mind a while ago as a compromise coilover because everyone seemed to love them, but I'm interested in hearing some negative feedback on them.
[/quote]

Theres quite a few unhappy people, if you go through the main thread they seem to be underdamped. Lots of people have been complaining about their bounciness even on regular daily driving. Ive had two friends ditch their setups because no matter what you adjusted it was still pretty much the same ride. You hit a bump and the chassis just seems to oscillate more then it should.

 

What spring lengths are going to ship with these?

I know you said 6" front and 5.5" rear at one point but that seems kinda short in the rear. Potentially run out of spring travel...

 

I run 5.5" 650 rear springs and haven't fully compressed them yet. within a 1/2" though with AutoX and Daily driving with a few bad bumps. One in particular that you'd think would bottom out the shocks at 55mph but doesn't. I have to go over it to work every day and typically slow to 35mph for it but tested my nerve and the suspension at 55. no issue. I'd bet 5.5" 550s would fully compress over the bump.

EDIT: one measurement I took probably only leaves 3/8" of travel left on my rear springs

 

The ASTs should be able to handle a good amount of spring on the off the shelf valving. When I had 4100s I had 700/600 and I know I could have gone a tad higher out back.

 

Thanks, I was thinking of using 550s so looks like 5.5" would indeed be too short at that rate.

 

It all depends on available stroke and damping.
Running a stock length damper with stock top hat at roughly 13" would be really close depending on the bump stop used. If you run the car higher or run a damper body length that's shorter than stock then you would for sure reach the block height of the spring.

 

And based on your rear shock length post, the 4150s are about .75" shorter than stock.

 

So then unless you run 12.25-.5 then you'd probably have issues with 5.5" springs

 

The recommendation if using spring tenders is 6in front and 5.5in rear. Without tenders, a 7in front and a 6.5in rear.

 

My test was done with my rear shocks at 4 of 12 clicks on compression. Soft. The KW clubsports are about the same length as stock. Overal, I have only about 7/8" to 1" of travel left before the shock body would bottom out but the 5.5" spring would bottom out first at my ride height. REAR Ride height of 13.3" with full tank of gas.

I think Eibach catalogue was updated and their not showing spring block heights anymore. Anyways.
KW catalog http://www.kw-suspension.com/pdf/kw_racing_catalog.pdf
1 newton = 0.2248089 pound-force
1 millimeter = 0.0393701 inch
0.2248089/0.0393701 = 5.710143
N/mm * 5.710143 = lb/in

in ref to 61mm ID race springs
130N/mm = 742# 130N/mm x 140mm(5.5in) springs can compress 2.8”
110/628# x 140mm = compress 73mm or 2.87”
100/570# springs 140mm long = compress 2.91”

corner weight of 750 will compress the 742# springs about 1.45". 1.35" of travel left. My 5.5" 650s compress around 1.4". Stock S2000 weight

make your own assumptions but I wouldn't run 5.5" springs if I was ordering the ASTs. 6" min. 7" would work too.
570# x 7.09"L = 3.74" compress
742# x 6.7”L = 3.46” compress