All Info is Verified by Links Unless Otherwise Noted

Calculations Done Using Spring Rates Given by TIC for Factory 2008 STi

Contents

A. Factory 2008 STi Spring Facts

B. After Market Springs
1. Agency Power Performance Springs
2. Cobb Tuning Sport Springs
3. Eibach Pro-Kit Springs
4. Espelir Active Down Springs
5. H&R Sport Springs
6. RaceComp Engineering Functional Lowering Springs
7. RaceComp Engineering Sport Lowering Springs
8. RSR Ti2000 Down Springs
9. Subaru JDM Pink STi Springs
10. Swift Sport Springs
11. Tanabe DF210 Springs
12. Tein S-Tech Springs

C. Springs Listed from Most Lowered to Least Lowered

D. Springs Listed from Highest to Lowest Spring Rates

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A. Factory 2008 STi Spring Facts

Link: Info Provided by TurnInConcepts after given facts by SoA
Front Spring Rate: 217lb/in
Rear Spring Rate: 194lb/in


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B. After Market Spring Facts

1. Agency Power Performance Racing Springs

Link: Agency Power Performance Racing Springs Subaru WRX STI 08+ (http://www.agency-power.com/catalog/agency-power-performance-racing-springs-subaru-wrx-sti-08-p-48008.html)

Front Drop: 1 1/4” (32mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 3/4” (19mm)
Rear Spring Rate &Increase: No Info Found
Skid Pad: No Info Found
Cost: $250 @ Agency-Power.com

2. Cobb Tuning Sport Springs

Link: CobbTuning.com - 08 STI Sport Springs (http://cobbtuning.com/products/?id=4211)

Front Drop: 7/8” (22mm)
Front Spring Rate & Increase: Estimated Rate of 240 lb/in based on Cobb's 10% Claimed Rate Increase
Rear Drop: 7/8” (22mm)
Rear Spring Rate & Increase: Estimated Rate of 232 lb/in based on Cobb's 20% Claimed Rate Increase
Skid Pad: from 0.94 g stock to 1.02 g
Cost: $250 at RallySportDirect.com

3. Eibach Pro-Kit Springs

Link: Eibach Springs - Performance Suspension, Lowering Springs, Shocks, Sway Bars, Coil-Overs and Wheel Spacers! (http://eibach.com/cgi-bin/htmlos.exe/05130.2.4462719504300025556)

Front Drop: 1” (25mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 1” (25mm)
Rear Spring Rate &Increase: No Info Found
Skid Pad: No Info Found
Cost: $270 at Vivid Racing

4. Espelir Active Down Springs

Link: None Found and Info UNVERIFIED

Front Drop: 1 1/5" (30mm)
Front Spring Rate & Increase: 241 lb/in & Estimated 11% Rate Increase
Rear Drop: 1" (25mm)
Rear Spring Rate & Increase: 162 lb/in & Estimated 16% Rate Decrease???
Skid Pad: No Info Found
Cost: No Info Found

5. H&R Sport Springs

Link: Subaru WRX & STi Coilovers, Lowering Springs & Suspension - H&R Sport Springs 2008+ Subaru Impreza WRX / STi Free Shipping (http://www.hopupracing.com/hrspsp20suim.html)

Front Drop: 1" (25mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 1" (25mm)
Rear Spring Rate & Increase: No Info Found
Skid Pad: No Info Found
Cost: $270 @ HopUpRacing.com

6. RaceComp Engineering Functional Lowering Springs *Still in Development*

Link: http://www.iwsti.com/forums/1867071-post25.html

Front Drop: 1/5”- 2/5" (5-10mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 1/5”- 2/5" (5-10mm)
Rear Spring Rate & Increase: No Info Found
Skid Pad: No Info Found
Cost: No Info Found

7. RaceComp Engineering Sport Lowering Springs *Still in Development*

Link: http://www.iwsti.com/forums/1867071-post25.html

Front Drop: 4/5” (20mm)
Front Spring Rate & Increase: No Info Found
Rear Drop: 4/5” (20mm)
Rear Spring Rate & Increase: No Info Found
Skid Pad: No Info Found
Cost: No Info Found

8. RSR Ti2000 Down Springs

Link: None Found and Info UNVERIFIED

Front Drop: 1” (25mm)
Front Spring Rate & Increase: 263 lb/in & Estimated 21% Increased Rate
Rear Drop: 3/5” (15mm)
Rear Spring Rate & Increase: 208 lb/in & Estimated 7% Increased Rate
Skid Pad: No Info Found
Cost: No Info Found

9. Subaru JDM Pink STi Springs

Link: japanparts.com : PARTS DATABASE (http://www.japanparts.com/db/partslist.php?dealer=1&car=134&middlesmall=3%3A9&maker=4&volkey=)

Front Drop: 3/5” (15mm)
Front Spring Rate & Increase: 285lb/in & Estimated 31% Increased Rate
Rear Drop: 3/5” (15mm)
Rear Spring Rate & Increase: 228lb/in & Estimated 18% Increased Rate
Skid Pad: No Info Found
Cost: $480 @ JapanParts.com

10. Swift Sport Springs

Link 1: Mann Engineering - Subaru Parts and Performance (http://www.mann-engineering.com/products/product.asp?cid=&ID=82)
Link 2: NASIOC - View Single Post - Coming Soon! Swift Sport Springs for 2008 STI (http://forums.nasioc.com/forums/showpost.php?p=23433290&postcount=12)

Front Drop: 1” (25mm)
Front Spring Rate & Increase: 143-251 lb/in & 10-15%
Rear Drop: 1” (25mm)
Rear Spring Rate &Increase: 118-235 lb/in & 10-15%
Skid Pad: No Info Found
Cost: $310 @ MannEngineering.com

11. Tanabe DF210 Springs

Link: RallySportDirect.com - Tanabe DF210 2008 Sti Springs (http://www.rallysportdirect.com/shop/tanabe-df210-2008-sti-springs-p-3808.html)

Front Drop: 1.1” (28mm)
Front Spring Rate & Increase: 246lb/in & No % Info Found
Rear Drop: 1.1” (28mm)
Rear Spring Rate &Increase: 174lb/in & No % Info Found
Skid Pad: No Info Found
Cost: $275 at RallySportDirect.com

12. Tein S-Tech Springs

Link: S.TECH (http://www.tein.com/products/s_tech_price_list.html)

Front Drop: 1” (25mm)
Front Spring Rate & Increase: 252 lb/in & No % Info Found
Rear Drop: 8/10” (20mm)
Rear Spring Rate Increase: 219 lb/in & No % Info Found
Skid Pad: No Info Found
Cost: $250 at RallySportDirect.com

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C. Springs Listed from Most Lowered to Least Lowered

1. New Agency Power Performance Springs (32/19mm)
2. Espelir Active Down Springs (30/25mm)
3. Tanabe DF210 Springs (28/28mm)
4. H&R Sport Springs (25/25mm)
5. Eibach Pro-Kit Springs (25/25mm)
6. Swift Sport Springs (25/25mm)
7. Tein S-Tech Springs (25/20mm)
8. RSR Ti2000 Down Springs (25/15mm)
9. Cobb Tuning Sport Springs (22/22mm)
10. RaceComp Engineering Sport Lower Springs (20/20mm)
11. Subaru JDM Pink STi Springs (15/15mm)
12. RaceComp Engineering Functional Lowering Springs (5-10/5-10mm)

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D. Springs Listed from Highest to Lowest Spring Rates

Insufficient data at this time.

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I will do my best to update this thread with new information and springs when it becomes available or is brought to my attention :D

-Steven

Nice write up here. =)

Thanks, it's Updated with the Espelir, H&R, and RSR Springs now.

Great info!

very helpful thread! Thanks for your time and efforts!

Thanks for the info...

Running the Swift STI Springs, too soft and jumpy, going to coilovers for that slammed washboard effect. But I have a WRX, why STI Spring. Well, the 09 has 08 STI Springs stock, I think.