Borla 40659 ProXS 2.5" Straight-Through Center/Offset Oval Stainless Muffler

Vehicle Fitment

Universal Fit -- Fits import and domestic cars, trucks, and SUVs. Weld-in installation. Reversible design allows offset inlet/center outlet or center inlet/offset outlet orientation.

Fitment Notes

• Universal muffler -- not vehicle-specific
• Un-notched necks designed for weld-in installation
• If clamping, use Borla 3" wide band clamps P/N 18004 (sold separately)
• Notched-neck version available as P/N 400481 for clamp-in installation
• Reversible design -- can be installed in either direction
• Verify available clearance before purchase: 19" overall length, 4.25" x 7.88" oval body

Features

• Straight-through core design -- no chambers or baffles restricting exhaust flow
• T-304 austenitic stainless steel construction -- will never rust
• 100% welded construction for strength and durability
• High-temperature continuous-filament fiber (CFF) acoustic packing for sound control
• Free-flow design for improved horsepower, torque, and fuel economy
• Reversible design for flexible installation orientation
• Compact oval body fits tight underbody spaces
• Natural mill finish -- can be brushed or polished
• Made in the USA

Specifications

• Part Number: 40659
• Product Line: Borla ProXS
• Inlet: 2.5" (offset)
• Outlet: 2.5" (center)
• Body Shape: Oval (4.25" x 7.88")
• Body Length: 14"
• Overall Length: 19"
• Neck Style: Un-notched (weld-in)
• Material: T-304 Stainless Steel
• Internal Design: Straight-through core
• Finish: Natural mill (brushed)
• Quantity: Sold individually
• UPC: 808422406598

Included Components

• 1x Borla ProXS oval muffler

Product Description

The Borla 40659 ProXS is a universal oval muffler built from aircraft-quality T-304 stainless steel with a straight-through core design. Unlike chambered or baffled mufflers that restrict exhaust gas velocity, the ProXS uses an unobstructed flow path paired with high-temperature continuous-filament fiber (CFF) acoustic material to deliver a deep, street-commanding exhaust tone without sacrificing power. The compact 4.25" x 7.88" oval body and 19" overall length make it ideal for tight underbody packaging where space is limited.

The reversible design allows the muffler to be installed with either the offset or center end serving as the inlet, providing maximum flexibility during custom exhaust fabrication. Un-notched inlet and outlet necks are designed for weld-in installation, though band clamps (Borla P/N 18004, sold separately) can be used as an alternative. The 100% welded T-304 stainless steel construction ensures corrosion resistance and long-term durability. Backed by Borla's Million-Mile Warranty and proudly made in the USA.