Dinan BMW G01 X3 M40i / G02 X4 M40i Valved Cat-back Exhaust Systems | D660-0099, D660-0099-BLK

Transform your BMW G01 X3 M40i or G02 X4 M40i with the Dinan Valved Cat-Back Exhaust System—a perfect fusion of performance, aggressive tone, and premium aesthetics. Designed for the enthusiast who refuses to compromise, this system delivers a deep, signature Dinan exhaust note while retaining factory valve functionality for versatile sound control.

Crafted from 100% T304 brushed stainless steel and expertly TIG welded, this high-performance exhaust system is more than just a visual upgrade—it’s a true auditory experience. A quad-tip M-inspired setup replaces the stock dual-tips, giving your M40i the premium, motorsport-ready look it deserves. Available with polished stainless or black ceramic-coated 3.75" tips, each set is laser-etched with the Dinan logo for a refined finish.

Key Features:

• Peak performance gains of +6 horsepower and +5 lb-ft torque

• Larger 83mm diameter piping (vs. 80mm stock) for improved exhaust flow

• 7 pounds lighter than stock (Dinan: 53 lbs | OEM: 60 lbs)

• M-inspired quad 3.75” (95mm) tips – black ceramic or polished finish

• Straight-through single-pipe design eliminates factory resonator/collector

• Helmholtz muffler chamber reduces drone while enhancing exhaust tone

• Fully functional exhaust valve: switch from refined to aggressive at will

• No cutting, welding, or modifications required – 100% bolt-on installation

• Compatible with both Pre-LCI and LCI models

• Includes mounting hardware and valve actuator brackets

Signature Dinan Sound, Unmatched Flexibility

At low RPMs, the retained OEM exhaust valve keeps things subtle and refined perfect for daily commuting or neighborhood cruising. Open the valve, and your M40i roars to life with a deep, aggressive tone that turns heads and enhances driver engagement. Paired with a Helmholtz muffler for drone mitigation, the Dinan cat-back system offers a premium auditory experience without sacrificing comfort.

Whether you're after performance, sound, or stunning aesthetics, the Dinan Valved Cat-Back Exhaust System delivers in every category. No gimmicks, just genuine performance and style engineered specifically for the G01 X3 M40i and G02 X4 M40i platforms.