Shirk's - Audi B9 S4 Build List (Former ECS Project)

Nothing says classy and fun like the S4, especially the B9 S4 featuring the new turbocharged 3.0 V6 and lightning-quick transmission. Our B9 S4 sports some elegant and tasteful additions developed right here in-house for this platform to help demonstrate just how incredible you can make this car without much effort. From visual improvements to suspension, engine performance, brakes, and more, our B9 S4 build list is your road map to upgrading your S4 with some of the best parts in the scene.

Shirk's IG - joshirk18

Fits:
Audi B9 S4

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Carbon Fiber Front Lip Spoiler - Audi B9 A4/S4

Hand-laid carbon fiber to upgrade your exterior styling

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 3146390

Mfg#: 019196ECS01A

Qty:

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On SALE Save 41%

Limited Qty Sale

$875.99

This product was last offered at the strikethrough price on
05-02-2026

$515.77 USD

Free Shipping

Lifetime Replacement

Carbon Fiber Grille Accent Set - Audi B9 A4/S4

Hand-laid carbon fiber to upgrade your exterior styling

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 3420220

Mfg#: 024314ECS01

Qty:

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On SALE Save 44%

Limited Qty Sale

$576.99

This product was last offered at the strikethrough price on
05-02-2026

$323.43 USD

Free Shipping

Lifetime Replacement

Audi B9 Carbon Fiber Antenna Cover

Add a unique, lightweight look to your B9

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 3468626

Mfg#: 024985ECS01

Qty:

Choose how many gift cards you would like below. You can set the denomination in your cart during checkout.

On SALE Save 20%

$100.99

This product was last offered at the strikethrough price on
06-13-2026

$80.79 USD

Free Shipping

on orders $49 and up

Lifetime Replacement

Front Bumper Reflector Film Set - Gunsmoke

Pre-cut Lamin-X film to cover both orange reflectors on the front bumper cover

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!
Fits pre-facelift models only - Through the 2018 model year

Brand:

ES#: 3141518

Mfg#: 020232ECS01

Qty:

Choose how many gift cards you would like below. You can set the denomination in your cart during checkout.

On SALE Save 25%

$47.99

This product was last offered at the strikethrough price on
06-13-2026

$35.99 USD

Free Shipping

on orders $49 and up

Lifetime Replacement

Rear Bumper Reflector Film set - Gunsmoke

Pre-cut Lamin-X film to cover both reflectors on the rear bumper cover

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 3149378

Mfg#: 020796ECS01A

Qty:

Choose how many gift cards you would like below. You can set the denomination in your cart during checkout.

On SALE Save 10%

$47.99

This product was last offered at the strikethrough price on
06-13-2026

$43.19 USD

Free Shipping

on orders $49 and up

Lifetime Replacement

Carbon Fiber Trunk Spoiler - Audi B9 A4/S4

Add a touch of style and real carbon fiber to your Audi

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 3141741

Mfg#: 019220ECS01A

Qty:

Choose how many gift cards you would like below. You can set the denomination in your cart during checkout.

On SALE Save 28%

Limited Qty Sale

$694.99

This product was last offered at the strikethrough price on
05-02-2026

$500.99 USD

Free Shipping

Lifetime Replacement

Audi B9 S4 Rear Diffuser - Gloss Black

Add some aggressive styling to your Audi!

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 4056580

Mfg#: 006077LA01

Qty:

Choose how many gift cards you would like below. You can set the denomination in your cart during checkout.

On SALE Save 20%

$420.99

This product was last offered at the strikethrough price on
06-13-2026

$336.79 USD

Free Shipping

Lifetime Replacement

Audi B9 S4 / A4 S-Line Rear Bumper Side Splitters - Gloss Black

Spice up the exterior of your Audi with gloss black spats!

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 4164511

Mfg#: 004751LA01

Qty:

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On SALE Save 25%

$133.99

This product was last offered at the strikethrough price on
06-13-2026

$100.49 USD

Free Shipping

Lifetime Replacement

Audi B9 A4 / S4 Flat Side Skirts - Gloss Black

Enhance your side profile with an aggressive look!

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 4163869

Mfg#: 001734LA01

Qty:

Choose how many gift cards you would like below. You can set the denomination in your cart during checkout.

On SALE Save 20%

$363.99

This product was last offered at the strikethrough price on
06-13-2026

$291.19 USD

Free Shipping

Lifetime Replacement

Carbon Fiber Mirror Cap Set - Audi B9 A4/A5/S4/S5

With Lane Change Assist

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 3411932

Mfg#: 024564ECS01

Qty:

Choose how many gift cards you would like below. You can set the denomination in your cart during checkout.

On SALE Save 20%

$413.99

This product was last offered at the strikethrough price on
06-13-2026

$331.19 USD

Free Shipping

Lifetime Replacement

This product has been superseded to ES#4140163

P3Cars Vent Integrated Multi-Gauge - Without Vent - (NO LONGER AVAILABLE)

Powerful plug-and-play multifunction display with OEM integration and color matching

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms
Fits left hand drive models only

Brand:

ES#: 3420235

Mfg#: LVP3AB9X

No longer available

ECS Billet Aluminum Sun Visor Clips - Pair

Never break another hook on your sun visor clip again!

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms 10X Entries For Our 25th Anniversary Sweepstakes!

Brand:

ES#: 4623665

Mfg#: 017491LAKT

Qty:

Choose how many gift cards you would like below. You can set the denomination in your cart during checkout.

On SALE Save 25%

$73.99

This product was last offered at the strikethrough price on
06-13-2026

$55.49 USD

Free Shipping

on orders $49 and up

Lifetime Replacement

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Shirk's - Audi B9 S4 Build List (Former ECS Project)

Shirk's IG - joshirk18