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USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Jul 12 - Jul 17
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Description
Catalytic Converter for California Grade CARB Compliant Universal Catalytic Converter MagnaFlow 337303Overview: Keep the check engine light off with MagnaFlow California Grade CARB Compliant Universal Catalytic Converter 337303. The Universal design allows the part to fit a wide array of vehicles (cutting and welding required), and the stainless steel construction of this spun body catalytic converter is highly resistant to corrosion. The single laser fusion weld of the spun body greatly reduces the possibility of a leak, and our compact, low mass
Overview:
Keep the check engine light off with MagnaFlow California Grade CARB Compliant Universal Catalytic Converter 337303. The Universal design allows the part to fit a wide array of vehicles (cutting and welding required), and the stainless steel construction of this spun body catalytic converter is highly resistant to corrosion. The single laser fusion weld of the spun body greatly reduces the possibility of a leak, and our compact, low-mass design also allows for greater thermal efficiency.
This direct-fit catalytic converter is designed to fit the 1986-1993 Mercedes-Benz 300E, 1993-1995 Jaguar XJ6, and additional vehicles. This replacement part is designed to meet or exceed California Air Resource Board requirements, and has undergone additional testing to be certified by CARB for legal use in CA/CARB restricted states for the listed vehicles.
| Brand | Interchange Part Number |
|---|
Application:
| Year | Make | Model | Submodel | Engine Size |
|---|---|---|---|---|
| 1990 - 1995 | Jaguar | Vanden Plas | 4L/L6 | |
| 1993 - 1995 | Jaguar | XJ6 | 4L/L6 | |
| 1994 | Jaguar | XJS | 4L/L6 | |
| 1988 - 1992 | Mercedes-Benz | 300CE | 3L/L6 | |
| 1990 - 1992 | Mercedes-Benz | 300E | 2.6L/L6 | |
| 1986 - 1993 | Mercedes-Benz | 300E | 3L/L6 | |
| 1988 - 1990 | Mercedes-Benz | 300TE | 3L/L6 | |
| 1983 - 1984 | Toyota | Starlet | 1.3L/L4 | |
| 1990 - 1992 | Daihatsu | Charade | 1.3L/L4 | |
| 1995 | Mazda | MX-3 | 1.6L/L4 | |
| 1988 - 1989 | Mercedes-Benz | 190E | 2.6L/L6 | |
| 1987 - 1988 | Mercedes-Benz | 260E | 2.6L/L6 |
Specs:
| Body Material | Stainless Steel |
|---|---|
| Sensor Port Count | 0 |
| Overall Length (In.) | 8 |
| Outlet Quantity | 1 |
| Inlet Attachment | Weld-On |
| Oxygen Sensor Location | None |
| Inlet Quantity | 1 |
| Heat Shield Attached | No |
| Outlet Attachment | Weld-On |
| Body Width (In.) | 4 |
| Body Shape | Round |
| Inlet Diameter | 1.75 |
| Inlet Orientation | Straight |
| Material | Stainless Steel |
| Body Length (In.) | 8 |
| Series | California |
| Body Height (In.) | 4 |
| Subtitle | California / CARB Compliant |
| Air Tube Adaptable | No |
| Title | California Universal |
| Type | Universal |
| Outlet Orientation | Straight |
| Outlet Diameter | 1.75 |
| Finish | Stainless Steel |
| Body Type | Spun |
| Substrate Material | Ceramic |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- 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
4.7 ★★★★★
Based on 1938 reviews
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Product Reviews
★★★★★ 5
Great product!
Style: 30 sqft
I can say this product makes a huge difference with road noise and is cleaner and easy to work with when applying compared to other mats that cost about the same price.
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Reviewed in the United States on February 14, 2026
★★★★★ 5
Very heavy and thick
Style: 30 sqft
I purchased mini brands of sound ending and this is by far the heaviest sound deadening I've ever ordered. I'm not installed yet but I have a good feeling that is going to work exceptionally in blocking sound. If weight is a concern for you I would recommend a lighter product however if sound quality and a quiet ride is your priority this is the one for you.
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Reviewed in the United States on March 18, 2026
★★★★★ 5
Siless Hybrid 3-in-1 - Far Exceeded my Expectations!!!
Model: SLH20025
I recently installed the Siless Hybrid 3-in-1 sound deadening mat in my vehicle, and I’m genuinely impressed. For just $80 for 25 square feet, this product delivers performance that rivals materials costing twice as much — and with far less hassle. If you're on the fence......Just buy it! You will not be disappointed.
Easy to Install: Unlike traditional sound deadening products that are stiff, sharp, and temperature-sensitive, this mat is soft, flexible, and easy to work with. I cut it cleanly with regular scissors and pressed it into tight spaces using just my fingers, so if in you don't have a roller or install tool, a good pair of scissors and your hands can get the job done. With other brands like Dynamat, the aluminum layer often leaves micro cuts on your hands and tears up your fingertips, but Siless does not due the acoustic layer being on top and above the aluminum layer that holds the butyl layer. So, it's very easy on your hands.
Even in cooler temperatures (around 50°F), I had no trouble applying it but it goes on better heated. If warm outside, I would leave the entire box out in the sun for at least 30 minutes when it's warm or heats it's very pliable and easy to mold. Make sure its where you want it because once applied it's not ever falling off. and it became even more pliable and easy to mold. No heat gun, no mess — just straightforward application.
I installed 40–50 square feet throughout the interior, covering everything except the headliner and the flooring forward of the rear seat. The difference in cabin noise is astonishing. I can turn my radio up concert loud with gut-punching bass, and from outside the car, it sounds like a factory sound system at mid volume. I was blown away by how well it contains sound — both inside out and outside in.
My exhaust is pretty aggressive and now is barely audible from inside the cabin. While driving, it almost sounds like a stock factory setup. The Siless matting actually changed the driving experience and feels refined.
If you're skeptical about sound deadening gimmicks, I get it, but this is the first product I've used and when I needed more, I went Stright to the 3 in 1 Hybrid matting and purchased it again. I love researching before buying and that's very uncommon for me to do.
Note: Proper installation is key, and it does take time and patience. But if installed correctly and in the right places, it works better previously used from paint-on sound deadening to Dynamat.
Update Nov, 2025
After using it this in 4 separate vehicles now. I feel the Siless’s 3 in 1 Hybrid has nailed it for best budget deadener that is better than dynamat extreme in performance and installation
Protip: buy a roll of 2-3” aluminum tape and tape the seams. After trimming the edges tend to very sticky between the panels. I ran a strip of aluminum tape over the seems to create a better seal and true moisture
I used it on four vehicles now and have I have not been paid to review and purchased every order myself.
3 in 1 Hybrid deadener by Siless is the best all around easy to apply sound deadner period!
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Reviewed in the United States on September 29, 2025
★★★★★ 5
Top quality
Model: SLH20025
This Siless Hybrid 3-in-1 sound deadening mat is easy to work with and feels high-quality. The butyl material is thick and pliable, making it simple to cut and fit into doors, floors, or panels.
After installation, road noise and vibrations are noticeably reduced, and it also seems to improve the overall cabin feel. No bad smell.
At 25 sq ft per roll, it’s a good value for anyone looking to dampen noise and improve car acoustics. Overall, a solid, effective option for automotive soundproofing. Used on a Fiesta ST.
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Reviewed in the United States on February 15, 2026
★★★★★ 5
Made a big improvement in cabin noise—highly recommend
Model: SLH20025
Siless Hybrid made a huge difference in reducing noise in the floor of my truck cabin. In some areas, there was basically just bare sheet metal between the inside and outside, so adding this really helped the truck feel more solid and noticeably quieter on the road.
I used Kilmat on the doors, and honestly I wish I had used Siless Hybrid there too, but it was too late by the time I realized the difference. This material is very sticky, easy to cut, and simple to apply, which made the install pretty smooth.
Just a heads-up: the tacky side gets messy and will bond to clothing really easily, so be careful during installation. Overall, I’d definitely buy it again—great product with real results.
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Reviewed in the United States on December 2, 2025
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