Lexus IS250 IS350 Midpipe With High-Flow Cats: Owner FAQ

By REMARK Exhaust | Published: 2026-11-04

Category: Anleitungen

Straight answers on fitment, sound, check-engine lights and daily driving for the Lexus IS250/IS350 V6 RWD midpipe with high-flow catalytic converters.

Quick answer

A high-flow midpipe with cats is the middle step between an axleback and a full catback: it replaces the restrictive OEM midpipe while keeping the factory-style exhaust layout. For a 2014–26 Lexus IS250 or IS350 V6 RWD, the REMARK midpipe with dual high-flow cats is a direct-fit option, but check your model year and drivetrain before ordering.

Why the midpipe matters more than the muffler alone

The OEM midpipe on the IS V6 is smaller and more restrictive than the 2.5-inch mandrel-bent piping in the REMARK kit. That restriction sits before the muffler, so changing only the axleback can leave flow gains on the table. The H-pipe design also helps balance the two banks of the V6, which affects tone and drone more than most owners expect.

What high-flow cats change in daily driving

The kit uses two 400-cell metal-core converters that are EPA approved. Metal-core substrates tolerate heat cycling better than ceramic, which matters on a daily-driven V6. Expect a slightly louder, freer exhaust note than stock, but not the raw smell or rasp of a catless setup. The trade-off is cost and a more involved install than an axleback.

Fitment exceptions you should not ignore

The kit is listed for the IS250/IS350 V6 RWD from 2014 to 2026. All-wheel-drive models and earlier generations use different underbody routing, so do not assume this midpipe will bolt up. If your car has aftermarket headers or a non-stock catback, confirm flange positions and pipe diameters before purchase, because the catalog does not list every combination.

Lexus IS midpipe questions, answered

Will this midpipe fit my IS250 or IS350?: It is listed for the 2014–26 IS250/IS350 V6 RWD. Check your model year, engine and drivetrain against that listing. AWD and earlier generations are not covered by this fitment. Measure your current midpipe flange-to-flange before ordering if your car is modified.
Does it replace the catalytic converters?: Yes. The OEM midpipe contains the factory cats, so this kit replaces them with two 400-cell high-flow units. It is not a cat-back; it is the mid-section only.
Will it throw a check-engine light?: The converters are EPA approved, but high-flow cats can still trigger a P0420/P0430 code on some cars. If a light appears, scan for codes and check for exhaust leaks at the flanges first. Keep your stock midpipe until the new one passes a few drive cycles without codes.
How loud is it compared with stock?: Expect a deeper, slightly louder note than the factory midpipe, with the resonators controlling rasp. It is not a straight-pipe sound. Pairing it with an axleback will raise volume further.
Can I install it at home?: It is a bolt-on midpipe, but the factory hardware is often rusted. Soak the flange bolts, use penetrating oil, and have replacement gaskets and bolts ready. A lift makes it far easier. Spray the bolts the night before and again an hour before you start.
Do I need a tune after installing it?: No tune is required for the midpipe alone. A tune becomes relevant only if you add headers or change the intake and want to optimize for them.

Product facts

Midpipe with HF catalytic converters - Lexus IS250/350 V6 RWD [2014-26]: Dual 400-cell metal-core high-flow catalytic converters, EPA approved, with dual straight-through resonators. You get a legal, heat-tolerant cat setup and resonator control in one midpipe instead of sourcing separate pieces.
Midpipe with HF catalytic converters - Lexus IS250/350 V6 RWD [2014-26]
Midpipe with HF catalytic converters - Lexus IS250/350 V6 RWD [2014-26]: 2.5-inch mandrel-bent piping with an H-pipe design. Mandrel bends preserve flow area, and the H-pipe balances the V6 banks to reduce uneven tone and drone.