Just to provide some information regarding STI damper/spring parts number that I came across when researching for S206 chassis parts. You'll notice the damper/spring part numbers are not the same for every kit even though they may look the same. And the only publicized spring rate by STI that I know of is the lowering spring option for 2008 WRX STI (Type A/B).

Here we go:

R205 SPRING AND STRUT KIT / STI Performance Package Damper Kit
Front damper RH ST20310ZR040
Front damper LH ST20310ZR050
Rear damper ST20365ZR000
Front spring ST20330ZR020
Rear spring ST20380ZR040

*Note: Looks like there is specific package for 5 doors: PKG1100006
STI - SPORT PARTS - WRX STI

STI NBR Challenge Bilstein damper kit
Strut (F) RH 20310ZR020
Strut (F) LH 20310ZR030
Shock absorber (R) 20365ZR010
Coil spring (F) ST20330ZR020 ※
Coil spring (R) ST20380ZR050

<tS>
Strut (F) RH 20310ZR040
Strut (F) LH 20310ZR050
Shock absorber (R) 20365ZR020
Coil spring (F) ST20330ZR020 ※
Coil spring (R) ST20380ZR040

<tS type RA>
Strut (F) RH 20310ZR080
Strut (F) LH 20310ZR090
Shock absorber (R) 20365ZR020
Coil spring (F) ST20330ZR050
Coil spring (R) ST20380ZR040

<S206 damper set >
Strut (F) RH 20310ZR060
Strut (F) LH 20310ZR070
Shock absorber (R) 20365ZR030
Coil spring (F) ST20330ZR020 ※
Coil spring (R) ST20380ZR080

Lowering spring

2008+ (Type A and B)
Front spring: ST20330ZR010 (5kg/mm)
Rear spring: ST20380ZR020 (4kg/mm)

2011+ (Type C and D) Manual transmission:
Front spring: ST20330ZR030
Rear spring: ST20380ZR060

2011+ (Type C and D) Auto transmission (A-Line for JDM EJ257).
Front spring: ST20330ZR040
Rear spring: ST20380ZR070

My impression with STI is they very specific when it comes to part number so I believe the damper/spring settings are different for each part number. I could be wrong of course.

Source of information:
STI S206
Japanparts.com
sti.jp

 

Hi dlheman,

Yes I'm only getting specific parts for the Type A-B. Just for the struts and springs I'm not sure if I should spend double to get R205 specifics as there's a lot of good reviews on the GTworx setup. Which setup are you currently running? Also, curious what rims you currently have?

 

I am still on standard shocks and spring, and my rim is Enkei GTC-01 19x8.5 +42 (I think that's the offset).

As to which suspension setup is better is hard to say because there needs to be a direct comparison. However being R205 suspension, it has got to be good.

 

Subaru Impreza WRX STI R205 continues the tradition, still not coming Stateside

You can even buy the R205 specific chassis parts to go along with the R205 damper kit.

Subaru Impreza R205 | Auto Express

 

Here's another review Car Feature>> Sti Impreza R205 - Speedhunters

 

Get the gtworx combo, it's a bigger upgrade imo and after reading the information in multiples threads that RCE had shared across different car forums, i would happily support this company.

 

I'm still thinking about it. Exchange rate to CAD virtually puts those 2 at the same price

 

I think if you want to get STI damper kit:

1. STI R205 damper kit to go with R205 chassis parts

2. STI Bilstein NBR Challenge damper kit to go with S206 chassis parts

Just remember the front flexible drawer stiffener for S206 chassis parts can be made to suit 08 to 10' STI by pre-tensioning it to 3.0mm if I'm not mistaken. In any case the manual provides the number.

Both the R205 and Bilstein NBR are listed as applicable for all GR/GV model years.

 

I'm leaning heavily towards option #1. Love genuine STi parts for some reason :x

I think I'm done trying to fit something that is not designed for my car, chassis.

 

Well, just take your time and decide carefully.

There are reviews out there for you to read and have a good idea of what the R205 is all about.

 

I think the JDM STI parts are awesome but the valving and spring rates on them is unknown which leaves a lot up in the air. Also, I have a feeling getting them serviced would be quite difficult in the long term. I think the GTWorx/Bilstein option would be the best choice, not only in price but the fact that you will have customer support through GTWorx/Bilstein (don't know how they are valved or spring rates so can't compare performance between them) and they come with limited lifetime warranty which is also a nice bonus.