Almost every exhaust decision comes down to one trade-off: titanium or stainless steel. Both are correct answers, but for different cars and different budgets. This page is the short version we give customers before they pick a variant.
The short answer
| Titanium (Gr2 / Gr5) | Stainless steel (304) | |
|---|---|---|
| Weight | About 40–45% lighter than steel for the same wall | Baseline |
| Typical wall | 0.8–1.2 mm | 1.2–1.5 mm |
| Corrosion | Excellent, including road salt | Very good; 304 resists better than 409 |
| Heat | Lower conductivity — holds heat in the gas, less underbody radiation | Conducts heat into the surrounding metal |
| Sound | Thinner, brighter, more resonant | Deeper, more damped |
| Welding | Needs full argon purge and clean tooling | Forgiving, standard TIG |
| Cost | Highest | Moderate |
| Best for | Weight-sensitive cars, show builds, high-heat turbo sections | Daily drivers, track cars on a budget, anything welded on site |
Titanium: Gr2 or Gr5?
Gr2 is commercially pure titanium. It forms and welds easily, bends without cracking, and is what most exhaust tube, bends and muffler bodies are made from. Gr5 (Ti-6Al-4V) is an alloy — noticeably stronger, but harder to form and less forgiving at tight radii. In practice: Gr2 for pipe, bends, midpipes and mufflers; Gr5 where you want a thinner, stiffer section that still takes load.
- Titanium straight pipe — Gr2
- Titanium straight pipe — Gr5
- Titanium straight exhaust tube — Gr2/Gr5, 1.0 mm wall
- Titanium straight exhaust tube — Gr2/Gr5, 1.2 mm wall
- Titanium Gr2 mandrel bend — 152 mm leg
- Titanium mandrel bend — 15° to 180°, 1.5–4 in
- Titanium perforated tube — 1.0 mm wall (muffler cores)
Stainless: 304 or 409?
304 is austenitic stainless with nickel in it — the default for aftermarket exhausts. It welds cleanly, polishes well and holds up to salt. 409 is a ferritic grade with much less nickel; OEMs use it because it is cheap, but it rusts sooner on a coast car. Every stainless part we list as SS304 is 304, not 409.
- Stainless steel straight tube 304 — 1000 mm
- Stainless steel 304 exhaust tube — 1.5 mm wall
- Stainless steel mandrel bend 304 — 152 mm leg
- 90 degree mandrel bend
- Straight tube 304
Where titanium earns its price
Three places, and only three:
- Behind the rear axle. The further the weight sits from the centre of the car, the more it costs you in handling. A titanium rear section removes the most kilograms exactly where they hurt most.
- High-heat turbo sections. Titanium handles sustained high temperature with a thinner wall, which keeps the gas hot and the engine bay cooler.
- Anything you have to lift by hand. A full titanium cat-back can be carried by one person; the stainless equivalent usually cannot.
Where stainless wins
If the car is welded, modified or repaired on site, stainless is the pragmatic choice — a weld that was not argon-purged on titanium will fail, and it will fail at the worst moment. Stainless also gives a deeper note, which is what most people actually want from a daily driver.
Mixing the two
You can join titanium to stainless without a bimetallic corrosion problem in a dry exhaust, and we sell the parts to do it: titanium male / stainless female V-band kit and stainless male / titanium female V-band kit. A common build is a titanium rear section with a stainless midpipe — most of the weight saving, a fraction of the cost.
Full systems in both materials
- BMW M3 G80 / M4 G82 / M2 G87 — titanium valved cat-back or stainless valved cat-back
- BMW M5 G90 4.4T (2025+) — titanium or stainless
- Porsche 911 (992) — titanium cat-back
- BMW 330i — titanium alloy valved cat-back or stainless valved cat-back
- BMW 3 / 4 Series (B58) — titanium cat-back or stainless cat-back
Also in Inconel
For turbo manifolds and sections that see sustained extreme heat, Inconel 625 is the next step up from titanium on temperature resistance, at a further cost penalty: Inconel 625 straight pipe, Inconel 625 elbow, Inconel 625 tubing.
Still not sure?
Match the material to the part you are replacing, not to the whole car. Downpipes and midpipes are usually stainless; the rear section is where titanium pays for itself. Browse material and heat management for the full stock list, or go back to the BMW chassis fitment guide to pick a system first.
Looking for numbers rather than a recommendation? The exhaust material comparison puts titanium, SS304 and Inconel 625 side by side with published density, strength, thermal conductivity and oxidation limits, with sources for every figure.
The decision, in one paragraph
For a car that sees road salt and year-round use, SS304 is the sensible buy — the saving is better put into fit than into alloy. Titanium earns its price where the mass sits at the end of the run and the system is meant to outlast the car, which in practice means a full cat-back or a long system rather than a short section. Mixing the two is normal: stainless where the heat is, titanium from the mid-section back.
Last reviewed: 2 November 2026.