• 15+ Years of Performance Parts, Tuning & Installation

STM Evo X GESi EPA Stainless High Flow Cat

  • Backed by real installs and tuning experience at FAST of West Chester

Everyday Low Price:

$849.00
$849.00
Shipping calculated at checkout.

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Earn FAST WC Points on this order — redeem on your next purchase
The STM stainless high flow cat for Evo X features a full stainless steel construction, tig-welded in house at STM and utilizes the 85030 GESi GEN1 ultra high output EPA compliant catalytic converter. Bolts right in place of your stock cat and uses the factory hanger. Both O2 bungs are included as pictured for your factory o2 sensor and and a wideband if you run one, as well as the extra plug if you don't.

Vehicle Fitment:
2008-2015 Mitsubishi Lancer Evolution X

Features & Specs:
• 300 Cell GESi Gen 1 (for up to 2016 vehicle models) G-Sport UHO EPA Converter (85030)
• Supports up to 850 HP 
• Hand Fabricated
• Tig-Welded
• Back-Purged
• Full Stainless Steel
• 3" 2-Bolt Exhaust Flange
• SS Laser Cut Flanges 
• Two O2 Bungs
• Gaskets and Hardware Included
• Bolts to Stock Downpipe and Cat-Back
• Fits with Stock-Placement Aftermarket Downpipe and Cat-Back
• Please check all local laws for street use before purchase
• Weighs 7.10 pounds

Made in the USA!
Lifetime Warranty on STM Parts to the original purchaser against manufacturing defects.
* This does not include the natural life of the converter *

Includes:
(1) STM Cat Pipe with GESi UHO 300 Cell Cat
(2) Remflex 3" Gaskets
(4) M10 x 35 Bolts
(4) M10 Flat Washers
(4) M10 Nuts
(1) O2 Bung Plug

Shipping Times: 1-10 Days
Hand crafted and welded in New York, please give our fabricators time to assemble your piece!

For Racing Use:
Please check all your local laws before purchase.

Notes:
The OEM Mitsubishi catalytic converters are not typically stocked by USA warehouses, but we can special order them from Japan (~3 months). 1584A350 is estimated at $2910.56.

Previous Part Numbers:
STM-EVOX-RP-GESI, STM-EVOX-RP-HFCSee more STM Parts
See more STM Products
  • Earn FAST points on this part!
  • Backed by real-world installs
  • FAST WC Team Approved
STM Evo X GESi EPA Stainless High Flow Cat

$849.00

Why Drivers Choose FAST of West Chester

  • I can't recommend this place enough. Being able to trust a shop in the performance world is big. The 2hr drive to get there, is worth knowing the job will be done right. Very happy to have found this shop, to
    support my builds going forward.

    Donald Wojnar

  • I recently had the pleasure of working with FAST of West Chester for some performance upgrades on my 2022 WRX, and the experience was nothing short of exceptional. I opted for a Borla S-Type exhaust and Cygnus Coilovers, and the team at FAST nailed the installation, fitment, and setup to a T.

    Adam Cranston

  • The team at FAST are excellence in every way. First, I consulted with Dave on mods for my HPDE track car. He listened and advised me on the best parts & mods to achieve my goals. He was patient & gave me space to research the options presented & worked with me through several changes before we built. Second, the build execution was flawless, proper heat shielding, bracing and poly everywhere. All components worked as advertised.

    Bryce Budd

  • This place has been my go to shop for all things Subaru. From simple service to performance parts and tuning, they have been top notch.

    William Brunell

  • Excellent shop. They installed a Cobb Stage 2 DP and Whiteline Sway bars and end links on my 2013 WRX. The work was done right and clean. The estimate was accurate. They were very knowledgeable, friendly and gave me the straight scoop on exactly what I was getting for the money
    and what I needed to get where I want to be with it. I'd recommend them
    to any car enthusiast.

    Devin Greco

Does it come with a warranty?

Most products we carry include a manufacturer warranty. Since we work with top performance brands, warranty coverage can vary by product. If you have questions about a specific item, reach out — we’re happy to help.

Do you offer installation help or advice?

Yes — we don’t just sell parts, we install and tune them too. FAST of West Chester is a real performance shop, and we’ve worked hands-on with many of the products we carry. If you have questions about fitment, installs, or building your setup, our team can point you in the right direction.

How fast is shipping?

Many of our products ship the same day or next business day, depending on availability. We work hard to get parts out fast so you can get your build moving without delays.

What’s your return policy?

Returns for exchange or refund are accepted within 30 days of receiving your order. Items must be in new, unused condition and in original packaging. If you have any questions, our team will help make the process easy.

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