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2015+ Subaru WRX-STI Flow Designs Rear Under Spoiler WIth Chassis Mounts & Rear Extension


Please Note: Pricing on our site is pricing for this one individual part picked up at our shop. Please contact us if planning on buying more than one FlowDesigns product as we will be able to offer discounts on multiple Flow products.

Please Note: Flow Designs products do not ship for free, please contact us so we can get you a custom shipping quote if you're not picking up. If you order first we will email you a shipping quote within 48hrs.

Suits WRX& STI


The new Flow Designs splitter set for Subaru WRX/STI (VA) include front & side splitters, rear spats & rear under spoiler extension. Every piece of this set has optional adjustable winglets to make exterior styling truly a custom artform. Everything is hand polished to satin black & easy to install!


Hardened Steel mounts bolts directly onto metal OEMlocationswithout having the need to drill any additional holes giving our under spoiler strength and stability.

Our suspendedspoiler can then be easily installed and adjusted on the car by up from 0mm - 20mm.
This designgives you the flexibility to run the spoiler conservativelyor more aggressive with just a simple 4mm Allen key wrench. Adjustments can be done in just a few minutes on the car.

Full movement can be seen in the video below. Once the desired position is set, tighten and you're ready to go.

Kit Includes:

  • Adjustable rear diffuser
  • Rear under spoiler extension
  • Pair of chassis mounts
  • Center support bracket
  • Mounting hardware
  • 2 Flow Designs Stickers
  • Fitting kit


  • 10mm thick polyethylene composite, bevelled edges


  • Hand polished satin black

Why do we use Polyethylene Composite for Flow Designs Splitters?

Strong, impact resistant, doesn't corrode or chip, and has excellent abrasion resistance (say from scraping on driveways and road all the time?)

Carbon Fibre is better isnt it?

As strong and light as Carbon fibre is, it CRACKS on impact or when under load and/or stress. Clear coat will eventually fades & cracks and become undesirable.

Installation Instructions