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Upgrade your BMW 3 Series with the K&N Engineering Part #knn33-2231 High-Flow Drop-In Air Filter, designed to enhance engine performance and airflow. Crafted from a layered, oiled cotton media, this filter effectively captures contaminants while improving overall airflow, resulting in increased horsepower and acceleration. Its innovative design allows for a direct replacement in your factory air box, making installation straightforward without the need for additional modifications. Built for durability, this reusable filter is engineered to last for the entire lifespan of your vehicle, backed by K&N's 10-Year/Million Mile Limited Warranty, providing confidence in its long-term performance and reliability. Whether you're looking to boost your car*s power or protect your engine from harmful debris, this filter offers a perfect blend of performance and protection. Maintenance is simple, as it can be cleaned and reused multiple times, saving you money and effort over the years. Suitable for select BMW 3 Series models from 1999 to 2003, this filter ensures a seamless fit and optimal performance, making it a must-have upgrade for enthusiasts seeking superior airflow and engine efficiency. Experience the difference with K&N's trusted quality and enjoy enhanced driving dynamics with a product designed for high performance and longevity.
Features:
Fitment:
1999 BMW 318ti Base
1999 BMW 323i Base
2000 BMW 323Ci Base
2000 BMW 323i Base
2000 BMW 328Ci Base
2000 BMW 328i Base
2001 BMW 325Ci Base
2001 BMW 325i Base
2001 BMW 325xi Base
2001 BMW 330Ci Base
2001 BMW 330i Base
2001 BMW 330xi Base
2001 BMW M3 Base
2002 BMW 325Ci Base
2002 BMW 325i Base
2002 BMW 325xi Base
2002 BMW 330Ci Base
2002 BMW 330i Base
2002 BMW 330xi Base
2002 BMW M3 Base
2003 BMW 325Ci Base
2003 BMW 325i Base
2003 BMW 325xi Base
2003 BMW 330Ci Base
2003 BMW 330i Base
2003 BMW 330xi Base
2003 BMW M3 Base
2004 BMW 325Ci Base
2004 BMW 325i Base
2004 BMW 325xi Base
2004 BMW 330Ci Base
2004 BMW 330i Base
2004 BMW 330xi Base
2004 BMW M3 Base
2004 BMW X3 2.5i
2004 BMW X3 3.0i
2005 BMW 325Ci Base
2005 BMW 325i Base
2005 BMW 325xi Base
2005 BMW 330Ci Base
2005 BMW 330i Base
2005 BMW 330xi Base
2005 BMW M3 Base
2005 BMW X3 2.5i
2005 BMW X3 3.0i
2006 BMW 325Ci Base
2006 BMW 330Ci Base
2006 BMW M3 Base
2006 BMW X3 3.0i
Order Processing
All orders are processed and shipped within 24 hours of purchase (excluding weekends and holidays).
Orders placed after 3:00 PM EST may ship the following business day.
Shipping Methods
Customers select their preferred shipping method and speed at checkout.
Shipping times are determined by the carrier and cannot be guaranteed by us.
Tracking information will be provided once your order has shipped.
Shipping Coverage
If your package arrives damaged, please notify the delivery driver immediately and contact the shipping carrier to file a claim.
You must report any missing or damaged items within 14 days of delivery.
After this time, we cannot be held responsible for lost or damaged items.
Return Window
You have 30 days from the date of delivery to request a return.
After 30 days, we are unable to accept returns, exchanges, or refund requests.
Eligibility
Items must be returned in their original condition—unused, unwashed, and with all tags and packaging intact.
Certain products may not be eligible for return (e.g., special-order items, customized products, or perishable goods).
Items that have been altered, installed, or modified cannot be returned.
Return Process
Contact our Customer Support team to request a Return Authorization (RMA) before sending items back.
Once your return is approved, you’ll receive instructions on where to send the product.
Customers are responsible for return shipping costs unless the item was defective or incorrect.
Refunds
Refunds are issued to the original payment method once the returned item has been received and inspected.
Please allow 5–10 business days for the refund to appear on your account.
In some cases, a restocking fee may apply (if applicable, this will be disclosed during your return authorization).
