SKU: 10844423116

Fabspeed Sport Cat Downpipe | BMW Z4 M40i

Sale price$916.65 Regular price$1018.50
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Ships within 48 hours · Estimated delivery Aug 17 - Aug 22

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Description

Fabspeed Sport Cat Downpipe | BMW Z4 M40iThe 2020 Z4 is BMWs latest incarnation of the Z4, keeping its reputation alive and well as a powerful and fun roadster. The Z4 M40i dramatically benefits, in terms of sports car sound and power, from a Fabspeed Motorsport Sport Cat Downpipe. Youll appreciate the more aggressive exhaust note and significant horsepower increase. These downpipes feature German made HJS 200 cell EURO 6 EC certified compliant trimetallic catalytic converters. We use 4 inch

The 2020 Z4 is BMW’s latest incarnation of the Z4, keeping its reputation alive and well as a powerful and fun roadster. The Z4 M40i dramatically benefits, in terms of sports car sound and power, from a Fabspeed Motorsport Sport Cat Downpipe. You’ll appreciate the more aggressive exhaust note and significant horsepower increase.

These downpipes feature German made HJS 200 cell EURO 6 EC certified compliant trimetallic catalytic converters. We use 4 inch piping from the engine side to the cat, and 3 inch tubing from the cat to the rest of the exhaust. These are the largest and highest flowing catalytic converters you can fit on the M40i 3.0L. Larger catalytic converters are better because they allow for more exhaust flow and the increased catalysts surface area allows for better exhaust gas filtering which means emissions compliance and will NOT trigger a check engine light. Our Sport Cat Downpipes are a direct bolt-on replacement for the factory Supra catalytic converter.

When we looked at the factory 12” long 700 cell ceramic core cats we immediately found an opportunity for improvement. The OEM Cats restrict exhaust CFM flow, limit sound and worst of all, rob performance. Replacing the OEM cats for a set of Fabspeed Sport Catalytic converter will net you improved performance with absolutely zero fear of a check engine light.

Why We Choose HJS Catalytic Converters:

HJS German imported catalytic substrate cores are made by EMITEC utilizing the highest grade stainless steel materials and Tri-metallic precious metal wash coats for high performance street and racing competition usage. HJS German 200 cell Trimetallic Euro 6 HE catalytic converters give the highest performance gains, improved sports car sound and maximum durability. Other brands of catalytic converters immediately deteriorate and fail over time as is typical. Some other companies and brands DO NOT even offer catalytic converters as they know that their catalytic converters will NOT work even when 100% brand new as they have no reliable quality solutions. The HJS German imported HD catalytic converters flow up to 90-92% of a straight pipe in most applications. The benefit is that you get the "straight pipe sound" while still being able to provide enough emissions scrubbing to prevent a check engine light. Typically no P420 and no P430 codes and your car smells clean with no need for a tune to pass emissions testing. It’s a win win solution for a sportier sound, more power, and a cleaner running car which prevents pollution. Not all HJS catalytic converters are the same. Size matters and directly correlated to power, sound, and durability. Fabspeed utilizes the LARGEST possible HJS Catalytic converter for maximum power and sports car sound. No short cuts ever.

FEATURES:

  • Simple bolt-on installation. Instructions included below
  • The largest HJS tri-metallic catalytic converter that will fit in the factory location
  • This HJS catalytic converter will support 1200HP+
  • Designed to fit Left hand drive and Right hand drive cars worldwide
  • Significant performance gains across the RPM band. Estimated +35HP gained over the factory unit
  • Even more power can be unleashed with a ECU tune. Please inquire
  • No tune required
  • Superior quality all German and USA components built in house by hand
  • TIG welded by our expert welders
  • T304 stainless steel construction
  • Fabspeed performance products are backed by Fabspeed's Lifetime Warranty
WARRANTY / INSTALLATION GUIDE
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 10844423116

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4.8 ★★★★★
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Keepin' it Real
Pawtucket, US
★★★★★ 3
Not full coverage
Size: Medium, Color: A-multicolor(6 Pack)
These are not full coverage and are the cheapest underwear in every way. The fabric is rough, and the seams around the edges of the leg openings are exposed. I ordered medium for my 28" waist and 38" hips. They fit... except for the buttcheek debut. I gave them to my 12 year old daughter to wear because she's not picky. Plus, they were cheap. She's happy. I'm still searching for full coverage undies. Update: The seller reached out regarding my review, and I'm impressed with their customer service. The cotton softened up upon washing and drying (no sand paper undies), and my daughter is very pleased with them.
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Reviewed in the United States on February 17, 2026
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Liz Newman
Houston, US
★★★★★ 5
Comfortable and cool. Does not ride up.
Color: 01-multicolour (4-pack), Size: Medium
Extremely comfortable. Stays cool. Ample coverage. Quality material. They do not creep up. I ordered a medium which I generally take a size small. I have reordered and will reorder again to add more colors to my collection.
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Reviewed in the United States on May 18, 2026
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Janola
Pawtucket, US
★★★★★ 5
Great Value for Cool Thigh Protection
Color: 02-multicolour (4-pack), Size: XX-Large
For the price, I'm not sure there are better women's boxer shortlettes anywhere. I've tried more expensive brands, and for quality and cooling, these are right up there. I have other bamboo viscose undies that still get gross when I get sweaty in the summer, but these, with the large mesh panel, really help wick away a lot of that moisture, keeping you feeling dryer and cooler. I find that the leg openings are comfortable and don't roll up! and the waist band doesn't dig, nor does it roll down. These do not provide any compression, and I wasn't looking for any. I just wanted some cooling, thigh protecting women's boxers that wouldn't break the bank. These are them! Bonus- I've washed them and put them in the dryer (following their instructions), and they haven't shrunk; they look about the same and are nice and soft.
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Reviewed in the United States on July 28, 2025
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Reviewer
Omaha, US
★★★★★ 4
Great for the entire family but expensive
So far so good. The brand of boxers we had been buying changed their style and construction so we needed to find an alternative. These have held up well so far to multiple weeks of frequent washing and wearing from the entire family. We did size up from the usual 6/M we normally buy and ordered large to prevent the legs from rolling up which worked out great. Our daughter likes the length and how soft the fabric is for wearing under skirts and gym shorts and liners stay put without moving or leaking as another reviewer mentioned. Our son says they are comfortable and fit well being just supportive enough without being constrictive. We all agree that there seems to be not enough fabric in the back as they tend to be much tighter across the backside than the front and that also causes the waist band to ride lower in the back than the front. These have better seam placement than some brands we tried with no seam across the lady bits and no seam down the middle of the back side so they are more much comfortable but the cost is also much higher and that is why we're only giving it 4 stars. These will stay in the rotation until we find something cheaper that both us and the kids like.
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Reviewed in the United States on January 24, 2026
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Brittany
Belleville, US
★★★★★ 5
Pregnant lady review! Soft, comfortable, cool.
Color: 03-multicolour (4-pack), Size: Large
So soft, comfortable and cool. I'm pregnant and I've gained weight in my legs. I love wearing dresses but my thighs were rubbing together too much. These are perfect to wear under dresses. I also wear them under my bibs at work and it keeps me from getting overheated but I don't have to worry about whether or not my underwear show since they just look like shorts. I wish these came in maternity. I just keep them below my belly. I'll be buying more for sure.
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Reviewed in the United States on April 8, 2026

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