I'd like to start up a guide so that people like me that want to compare springs can view all the different springs available and how low they drop the car, load capacity, Etc... I'm guessing cutting and pasting would be a good idea? I'll start it off with some of the companies and hopefully you guys will add to it. (BTW this is for the coupe as I guess the sedan is different) If I am wrong on any of these please let me know!

Brand Drop F/R Load capacity

RS*R 1.0"Front/1.2"Rear Front 315lbs Rear 315lbs
Eibach 1.1"Front/1.0"Rear
H&R 1.1"Front/1.0"Rear
Tanabe NF210 2.2"Front/1.7"Rear
Tanabe DF210 1.5"Front/1.5"Rear
Tein H-Tech 0.6"Front/0.3"Rear Front 325lbs Rear 269lbs
S-Tech 1.2"Front/0.9"Rear Front 358lbs Rear 274lbs

Any others???

 

ESPELIR ACTIVE GT
Part no: ESG059
Front (lower) 10mm
Rear (lower) 10mm
Spring Rate (Front-Rear) 7.3-9.2

Spring Tech
Front 1.8"
Rear 1.8"

Hotchkis
Part Number: 19413
Front 0.5 340 lbs/in
Rear 0.75 330 lbs/in

RS-R SUS Down
Part No. RSR-30-N200

RS-R Ti2000 (Titanium mix)
Part No. RSR-32-N200

Tanabe Super Down
TDF073
Front 2.0"
Rear 2.5"

Tanabe Grip
TGF063
Front 1.24"
Rear 1.5"

Tanabe Normal
TNF073
Front 1.25"
Rear 1.5"

Intrax
Part No. 60.1.007
Front - 1.2"
Rear - 1.2"

There's a ton more....

 

jsut to let you guys know

350z h techs on my g35 coupe. dont know how much it lowered total but with the 225 45 18 and 245 45 18 rear im at 26 1/8 to fenderlip from ground in front and 27 in rear

 

B+G
Front 1.2"
Rear 1.2"

Eibach Pro Kit
1.1"Front/1.0"Rear

ESPELIR ACTIVE GT
Part no: ESG059
Front (lower) 10mm
Rear (lower) 10mm
Spring Rate (Front-Rear) 7.3-9.2

Hotchkis
Part Number: 19413
Front 0.5 340 lbs/in
Rear 0.75 330 lbs/in

H&R
1.1"Front/1.0"Rear

Intrax (350Z)
Part No. 60.1.007
Front - 1.2"
Rear - 1.2"

Intrax (G35)
Part No. 60.1.048
Front 1.8"
Rear 1.6"

RS-R SUS Down
Front 1.0" / Rear 1.2"
Part No. RSR-30-N200 or N400???
Front 315lbs Rear 315lbs

RS-R Ti2000 (Titanium mix)
Part No. RSR-32-N200 or N400???

Spring Tech
Front 1.8"
Rear 1.8"

Sprint
Front 1.8"
Rear 1.8"

Tanabe Super Down
TDF073
Front 2.0" or 1.5" Front 1.5" Rear <-- I saw that some where!?
Rear 2.5"

Tanabe Grip GF210
TGF063
Front 1.24"
Rear 1.5"

Tanabe Normal NF210
TNF073
Front 1.25" (performancenissanparts.com says 2.2" Front / 1.7" Rear)
Rear 1.5"

Tein H-Tech
0.6"Front/0.3"Rear
Front 325lbs Rear 269lbs

Tein S-Tech
1.2"Front/0.9"Rear
Front 358lbs Rear 274lbs

I consolidated the lists, added to it and alphabatized them. Found a few conflicts... Lets keep this going!

 

gsedan35 made a comprehensive list somewhere. run a quick search.