Most owners buy an exhaust and then find out what it sounds like. It works far better the other way round: decide the character first, then choose the components that produce it. Character has separable parts, including volume at idle, volume inside the cabin at a steady cruise, tone under load, and whether the system rasps when cold.
The common mistake is treating loudness as one dial. A system can be calm at idle and harsh at cruise, or loud outside and quiet inside, depending on how much absorption volume the muffler carries and where the resonator sits. Decide each category before ordering, because the parts that fix one can spoil another.
Outside sound is what a spectator or a neighbour hears, and it is dominated by the rear section. A straight-through core with absorption packing gives a broad, even note that holds its character across the rev range. A chambered or valved design gives a sharper edge and can change character on demand, which suits owners who need a quiet leaving-the-house mode and a louder open mode.
Wall thickness matters here as much as internal layout. A thin-wall titanium exhaust muffler rings with a higher, more focused pitch, while a heavier stainless steel muffler of the same design sounds fuller and flatter. Neither is better; they are different instruments. Decide which matches the car and how often you want to hear it at full load.
Cruise noise is where most exhaust regret comes from. Drone is a standing wave that builds at a particular road speed and load, and it depends on pipe length, cross-section and the position of any resonator. Shortening a system or deleting a resonator usually moves that problem to a different speed rather than removing it, which is why revised rear sections so often trade one annoyance for another.
If the car covers long journeys, treat cabin noise as the first requirement and outside sound as the second. A system slightly quieter than you imagined is easy to live with. A system that hums on every motorway gradient will be replaced within a season, and the second purchase costs more than doing it properly the first time.
Material choice is a filter laid over the layout. Titanium tends to give a dry, ringing quality with a fast decay, and it changes pitch noticeably as it heats through. Stainless steel tends to give a denser, more consistent note that stays closer to the same voice from cold start to working temperature. Both can be tuned with the same tools: core design, packing and pipe length.
The practical rule is to choose the material for the durability and weight you want, then tune the sound with the muffler and resonator. Trying to buy a tone with material alone leads to expensive experiments. A workshop that already builds both grades can usually say which combination suits a given engine and use case before anything is fabricated.
Once the character is decided, agree on a way to verify it. A simple phone recording at a fixed distance, taken at idle and at a steady cruise, gives a reference to compare against after fitting. Subjective memory is unreliable, especially after weeks of waiting for parts, and it almost always drifts towards wanting more volume.
Agree the target before fabrication starts, not after. If a supplier knows the system must stay quiet at cruise and only open up under load, that requirement shapes resonator position, packing density and rear section geometry from the first drawing. Changing the brief afterwards is possible, but it is a rebuild rather than an adjustment.
A car driven daily on the same routes needs a different target from a weekend car. Daily drivers benefit from a system that is honest but restrained, with the excitement arriving above the speeds used for commuting. Weekend and track cars can accept a narrower band because the owner chooses when to be in it.
Whatever the target, leave a margin. A system already at the limit of what you find acceptable when it is new will become intolerable as packing settles and joints bed in. Choosing slightly below your maximum gives the sound somewhere to go and keeps the car enjoyable for as long as you own it.
