The MagnaFlow SPEQ Series #19828 cat-back exhaust is engineered for BMW G20, G22, and G23 M340i/M440i and xDrive models equipped with the 3.0L B58 inline-6. Designed to improve exhaust flow, amplify performance sound, and enhance visual appeal, it aggressively elevates the character of modern BMW performance. Constructed from mandrel bent 3” 304 stainless steel tubing with a 3.5” front pipe, it offers excellent durability and corrosion resistance. A stamped Y-pipe smoothly merges exhaust pulses for improved efficiency, while the straight-through design is dyno proven to support power gains for both stock and high output applications. Sound is managed through dual 5x8” straight-through mufflers and an NDT resonator, producing a deep, aggressive performance tone under acceleration while eliminating drone at cruising speeds. The result is a strong, assertive exhaust note that stays controlled in daily driving and opens up with pops and cracks when you get on or off the throttle. The system features interchangeable tip options secured with racing bred V-band clamps for a leak free, heat stable connection. Choose quad 3.5” black chrome tips with laser etched MagnaFlow “MF” logos or reuse factory tips. OEM valve functionality is retained by MagnaFlow’s cast stainless valves, allowing full integration with all driving modes. Designed as a direct replacement for factory components behind the catalytic converters, the system includes band clamps, laser cut logo brackets, and all necessary installation hardware for a secure, precise fit, achieved through 3D scanning and CNC robotic manufacturing ensuring a true direct-fit installation. Backed by MagnaFlow’s limited lifetime construction warranty, this cat-back delivers a measurable upgrade in sound quality, flow efficiency, and overall power. Designed with a focus on real world performance, it enhances the B58 with a power focused exhaust tone and the premium construction demanded by modern high output performance.

This Part Fits:

Year	Make	Model	Submodel
2020-2024	BMW	M340i	Base
2020-2024	BMW	M340i xDrive	Base
2021-2024	BMW	M440i	Base
2021-2024	BMW	M440i xDrive	Base

Shipping Overview

What is your shipping cutoff time? 

Cutoff time for in stock items is 2PM CST for items shipping with UPS.  USPS cutoff time is 10AM CST.   If you need a product by a specific date, please call us to find out if its possible to meet your deadline before ordering. Please be aware that there may be discrepancies with shipping calculators or “in stock” status of a product. 

 

Is shipping free? 

Orders over $149 qualify for free shipping within the lower 48 United States. We will select the most economical shipping option for our free shipping option.  If you'd like expedited service, please select that option during checkout.  Unfortunately, shipping to AK/HI or International we cannot offer free shipping, due to the extra costs incurred.  

 

How long will it take to get my stuff? 

Most in stock orders will ship the same day, if ordered before our cutoff times.  Custom items will ship when they are completed, please inquire for timelines on custom items (as this will vary).  We are located centrally in the US (St Louis MO) - so most items arrive within 2-4 days to the lower 48 US.  You will receive a tracking number when your item ships, allowing you to keep track of it at all times.  

 

I am an international customer, are fees / duties included in the shipping costs?

No, these fees will need to be paid by our international customers.  

 

How can I get a quote for shipping?

Please add the item in your cart and proceed through the checkout process. The system will display all the options we offer, along with a price. 

 

Refund / Exchanges

We have a 30-day return policy on non custom items, which means you have 30 days after receiving your item to request a return. 

To be eligible for a return, your item must be in the same condition that you received it, uninstalled and in its original packaging. You’ll also need the receipt or proof of purchase. 

To start a return, you can contact us at sales@retroshop.us. If your return is accepted, we’ll send you instructions on how and where to send your package. Items sent back to us without first requesting a return will not be accepted. 

You can always contact us for any return question at sales@retroshop.us.

Damages and issues 
Please inspect your order upon reception and contact us immediately if the item is defective, damaged or if you receive the wrong item, so that we can evaluate the issue and make it right.

Restocking Fees 
On non customized (returnable items), a restocking fee of 5-15% may be held from your refund.  Some items are special ordered in for customers, and if we have to return them to our suppliers, we may have a restocking fee for doing so.  If there are any questions on the restocking amount, please email us at sales@retroshop.us.

Exceptions / non-returnable items 
Certain types of items cannot be returned, like custom products (such as special orders or personalized items).  Please get in touch if you have questions or concerns about your specific item. 

Unfortunately, we cannot accept returns on sale items or gift cards.

Exchanges 
Please contact us for any exchanges at sales@retroshop.us.

Shipping Charges
Shipping charges are not refunded.  If you selected our free shipping option, the amount we paid to ship the item to you will be deducted from your return.

Refunds 
We will notify you once we’ve received and inspected your return, and let you know if the refund was approved or not. If approved, you’ll be automatically refunded on your original payment method. Please remember it can take some time for your bank or credit card company to process and post the refund too.