Resonator removal and backbox delete.

These are the two silencers people mix up, and they do different jobs. We look at both on the ramp before we recommend one.

The resonator — often the centre or middle box — takes the harsh, raspy frequencies out of the exhaust. Removing it makes the car sharper and a bit louder. It is usually the smaller job, and on a lot of cars it is the right first step if the rear box is still solid.

The backbox is the rear silencer. It does most of the quietening. Taking it off, or replacing it with a smaller sports box, is the change you hear from outside the car. A straight delete is the loudest and the cheapest, and it is also the one that drones at seventy miles an hour. If the car is a daily, we will usually steer you toward a sports back box or a valve rather than an empty pipe under the bumper.

Neither of these jobs removes the catalytic converter. The cat sits further forward. It stays put unless we are doing a separate downpipe, and that is a different conversation on the exhaust systems page.

What actually changes

A resonator delete on its own will not turn a quiet diesel into a race car, and a backbox delete will not fix a blowing flexi at the turbo. If the centre section is rotten, a neat delete is a waste of a weld — you need pipe, not a hole. We would rather sell you a proper section.

A sports back box keeps some silencing, gives a deeper note, and still looks finished at the bumper. That is what a lot of the cars in the gallery are wearing: tips lined up, a stainless centre section, and welds you can see. Alignment matters as much as the sound. A tip that sits high on one side is the thing you will look at every time you walk away from the car.

Why this job, not a full system

• The note, without the whole billIf the front and mid sections are sound, changing the silencer that is actually the problem is the honest quote.
• Rot replaced, not patchedA blowing or crushed rear box is cut out and welded back in stainless, with hangers that still reach.
• Drone is discussed firstWe will say when a straight delete is the wrong daily, and offer a sports box or a valve instead.
• The bumper still looks finishedTips are refitted square. A louder car with a crooked outlet is not a finished job.