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- Made in theMade to orderShips in 4-6 weeks
Ready to transcend your S58 into something that feels like a Porsche GT3? No more larping, just straight mogging. The MACH-1 starts with a 3-inch equal-length upper section that merges into our signature 4-inch oval mid-section. That design is what gives the car its bold, GT3-inspired character. It completely transforms the sound of the S58, eliminating the platform's notorious rasp and replacing it with a smooth, refined exhaust note. It sounds incredible with both catted and catless downpipes, delivering a high-pitched, exotic tone under partial and full throttle while holding a deep, rich, masculine note at idle. Fitment and clearanceMost aftermarket systems scrape heavily on lowered cars, and plenty of them scrape even at stock ride height. We tested the MACH-1 on both. It clears exceptionally well with no scraping, and the included drop brace replaces the factory brace to give you additional clearance where it matters. Commonly asked question:Is this mid-section different from the M2 G87 version? No, it is not. The only difference is due to chassis constraints, not a difference in design or flow dynamics. They are both MACH-1. What you getOur complete mid-section, which bolts directly to the factory rear muffler. It's also compatible with any aftermarket rear section designed to connect to the factory mid-section. All installation hardware comes with the kit, so there's nothing extra to source. Specifications Material: T304 stainless steel Construction: full back-purged TIG welds Sizing: 3-inch equal-length upper → 4-inch oval mid-section → 2.75-inch outlets Fitment: BMW G80/G82 M3/M4 (2021+) Includes: INR drop brace (replaces factory brace) and all installation hardware Build timeEvery system is made to order. From the time payment is received, current lead time is stated above and ships within that range.
from $1,650 - Made in theMade to orderShips in 4-6 weeks
Ready to transcend your S58 into something that feels like a Porsche GT3? No more larping, just straight mogging. The MACH-1 starts with a 3-inch equal-length upper section that merges into our signature 4-inch oval mid-section. That design is what gives the car its bold, GT3-inspired character. It completely transforms the sound of the S58, trading the platform's notorious harshness for a smooth, refined exhaust note. It sounds incredible with both catted and catless downpipes, delivering a high-pitched, exotic tone under partial and full throttle while holding a deep, rich, masculine note at idle. Resonated as standard, non-resonated by request Every G87 MACH-1 ships resonated by default, with an option to opt-out, and that comes down to the chassis. The M2 sits on a shorter wheelbase than the G80/G82, so the rear portion of the mid-section has less length to work with after the merge. Less tubing after the merge means less room for the S58's harmonics to settle before they reach the rear section, and on this chassis that showed up as a touch more energy through the 2 to 3k range. Rather than compromise the design to work around it, we built resonators to handle it. They are made in house to our own spec, not pulled from a catalog. The core, the chamber length, and the placement were all developed around our 3-inch equal-length upper, the 4-inch oval mid-section, and the specific length the G87 gives us, which is why a generic resonator cannot do this job without flattening the whole tone. The result is a system that stays clean at cruise with no drone, and a top end that loses none of its exotic character. Refinement without restriction. Every unit takes additional material, additional fabrication time, and additional TIG work over a straight-through build, and that is reflected in the price. Non-resonated. Full unrestricted mode. Nothing in the path, nothing tuned out, maximum top-end character on full throttle. The tradeoff is honest: on this chassis you keep some of that 2 to 3k character the resonators are there to manage. If you chase the top end and do not spend your life at part throttle, this is the one. Select it at checkout. Commonly asked question Is this mid-section different from the G80/G82 M3/M4 version? It is the same MACH-1 design with the same flow dynamics. The rear portion differs only where the chassis requires it, and that shorter run is exactly why the M2 version ships with our resonators as standard. Same system, tuned for what the G87 asks of it. Fitment and clearance Most aftermarket systems scrape heavily on lowered cars, and plenty of them scrape even at stock ride height. We tested the MACH-1 on both. It clears exceptionally well with no scraping, and the included drop brace replaces the factory brace to give you additional clearance where it matters. What you get Our complete mid-section in your choice of resonated or non-resonated, which bolts directly to the factory rear muffler. It's also compatible with any aftermarket rear section designed to connect to the factory mid-section. All installation hardware comes with the kit, so there's nothing extra to source. Specifications Material: T304 stainless steel Construction: full quality TIG welds Sizing: 3-inch equal-length upper → 4-inch oval mid-section → 2.75-inch outlets Configuration: resonated (custom INR resonators, standard) or non-resonated Fitment: BMW G87 M2 (2023+) Includes: INR drop brace (replaces factory brace) and all installation hardware Build time Every system is made to order. From the time payment is received, current lead time is stated above and ships within that range.
from $1,650 - Made in theMade to orderShips in 2-4 weeks
Purpose-built downpipes for the S58 platform, fabricated in-house to replace the restrictive factory units and let the turbos breathe the way they were meant to. The factory downpipes choke the S58 right off the turbine housing. Ours hold a full 3.0-inch cross-section from the outlet down, with a gradual taper only where it meets the mid-pipe, so flow is never pinched where it matters most. The result is reduced backpressure, faster spool, and a noticeably more aggressive exhaust note. Each pipe is hand-formed from T304 stainless steel and joined with fully back-purged TIG welds for clean internal flow and long-term durability under heat. Mandrel-bent tubing maintains cross-section through every bend, and smooth-radius routing keeps turbulence down where the factory design compromises. Three catalyst configurations. 400-Cell GESI Catted is the setup for anyone who needs the car to pass and stay quiet on the dash. GESI's EPA-registered high-flow cats are the most advanced units they build, and they light off fast: operational efficiency inside about 9 seconds of a cold start, which is what keeps the catalytic efficiency CEL from ever showing up. The substrate is 304 stainless furnace-brazed to the mantle, so it holds together under the sustained heat a boosted S58 puts through it, rated up to 1500°F. Each cat handles up to 500 hp and is built specifically for forced induction, so you're not giving up power to run it. EPA compliant for OBD2 vehicles, 1996 and newer, except in California. 200-Cell Catted runs high-flow 200-cell catalytic sections to cut emissions and tame volume for daily driving while still flowing far better than stock. The lower cell density trades some emissions capability for a freer-flowing, more aggressive character than the 400-cell. Non-Catted deletes the catalytic sections entirely for maximum flow and the most aggressive tone. Intended for off-road or race use and may not be emissions-compliant in all regions, so confirm local regulations before ordering. Heat-Wrapped or Bare. Every configuration is available wrapped in high-temperature thermal barrier. Bare stainless is offered on non-catted pipes only. In a bay as tight as the S58's, the wrap's biggest job is heat management: it pulls a meaningful amount of radiant heat off everything packed around the turbos, including wiring, sensors, and the intake charge sitting nearby. Lower under-hood temps mean more consistent power on repeat pulls and less heat soak into surrounding components. Keeping that heat in the pipe also helps maintain exhaust velocity and scavenging downstream of the turbo. Bare stainless is the choice if you want the raw look under the hood or plan to run your own coating. Direct bolt-on with no cutting or modification required. Retains factory sensor locations and pairs with the INR Mach-1 mid-section for the full system. Specs Material: T304 stainless steel Construction: full back-purged TIG welds Tubing: 3.0-inch mandrel-bent, smooth-radius bends Configurations: 400-cell GESI catted / 200-cell catted / non-catted Catalyst (400-cell): GESI EPA-registered, OBD2 compliant, 500 to 850 hp per cat, rated to 1500°F Finish options: Heat-wrapped (high-temp thermal barrier) on all configurations / Bare stainless on non-catted only Hardware: all mounting hardware included Fitment: 2021+ BMW G80/G82 M3/M4 (RWD and xDrive, incl. Competition), 2023+ BMW G87 M2
from $599.99
What we do
Services
Custom Fabrication
Full systems, downpipes, headers: built for your car when the catalog doesn't cover it.
Part Installation
What we build and what you bring, fitted clean, torqued to spec, road-checked.
Maintenance
Fluids, brakes, inspections and diagnostics, by the hands that do the fabrication.
Detailing
Paint correction and protection, under shop lights that don't forgive shortcuts.
Portland, Oregon · By appointment
Who we are
“I was seventeen when I started INR. What I had was a gravel driveway, a set of tools, and an obsession I couldn’t shake.”
