MBRP S6003P 4in AL Cat-Back w/ Downpipe for 2005 Chevy/GMC 2500/3500HD 6.6L

Vehicle Fitment

• 2005 Chevrolet Silverado 2500HD/3500 (6.6L V8 Duramax LLY, LT trim)
• 2005 GMC Sierra 2500HD/3500 (6.6L V8 Duramax LLY)

Fitment Notes

• Specific to the 2005 model year with the 6.6L Duramax LLY engine only
• Includes front downpipe as part of the system

Features

• Armor Lite Series construction - heavy-gauge aluminized steel for durability and value
• Includes downpipe for a complete exhaust replacement
• Replaces the restrictive factory exhaust to improve airflow
• Delivers a deeper, more aggressive diesel exhaust tone
• Improves throttle response under load, including towing
• Fully sealed tubing for rust resistance
• Single side exit configuration
• Tour Profile tuning for daily-driver usability

Specifications

• Tubing Diameter: 4in
• Exhaust Type: Cat-Back with Downpipe
• Exit Configuration: Single Side
• Series: Armor Lite
• Profile: Tour
• Material: Aluminized Steel
• Warranty: 1-Year

Included Components

• 1x MBRP S6003P Cat-Back Exhaust System with Downpipe (Aluminized Steel)

Product Description

The MBRP S6003P is a 4in cat-back exhaust system with an included downpipe, built specifically for the 2005 Chevrolet Silverado and GMC Sierra 2500HD/3500 with the 6.6L Duramax LLY engine. As part of MBRP's Armor Lite Series, it's designed for Duramax owners who want a meaningful performance upgrade without stepping up to a premium stainless steel system.

By replacing the restrictive factory exhaust, this system improves airflow, helping the Duramax breathe easier and respond more quickly under load - whether towing heavy or driving daily. The heavy-gauge aluminized steel construction offers solid corrosion resistance and fully sealed tubing for long-term rust resistance, while delivering a deeper, more aggressive diesel tone than stock.

Because this system includes the downpipe, it offers a more complete replacement than cat-back-only options, simplifying installation for owners looking to upgrade the full exhaust path. Backed by MBRP's 1-year warranty, the S6003P is a solid, budget-conscious choice for 2005 LLY Duramax owners.