Legal to have silence muffler in middle?

[fv43576]

My son's Citoren C3 2004, he want double exhaust to make look nice because he done good job to his car and it looks sport. I am welding for him as long it is legal, he want a silent muffler move to the middle of car with 'y' pipe from muffler two pipe to the rear end of car or it have to be two muffler both at rear end?

[GiveMeABreak]

Depends on the type of exhaust it is. If it going to make the car noisier - the answer is no as a general rule, regardless if it still meets emissions requirements. A police officer only has to think it is too noisy and you're booked!
Quote from Norfolk Constabulary:

Exhausts:
The vast majority of large or big bore exhausts are illegal for use on public roads. The fact they may have passed an MOT test is irrelevant as this only checks for exhaust gasses and emission legislation compliance. Big bore and sports exhaust systems are usually fitted to increase the sound emitted and this contravenes the Type Approval of the vehicle, which is an offence. There is no requirement for a police officer to measure the sound level from the exhaust system, it only requires an opinion that the system is not standard and that it is noisier than a normal vehicle of the same specification.
It is not an offence to sell these exhaust systems, but it is an offence to fit one to your vehicle and drive it on a public road. Motorists who do so could be reported to court and may face a fine and court costs.

Quote from GOV.UK:

Modified exhaust systems
It’s illegal to modify the exhaust system to make a vehicle noisier after it has been ‘type approved’ (checked it meets environmental and safety standards).
The police can also take action if your vehicle’s silencer doesn’t work in the way it was designed or if you’re driving in a way that creates too much noise.

Regardless, you'll need to notify the insurance company as it is a modification to the vehicle - anything that usually makes it look faster or 'boy racerish' increases risk in the eyes of the insurers, as it could encourage dangerous driving.

There's nothing wrong in fitting a chrome tip to your tailpipe as this isn't going to make it noisier, but always better to notify insurance just in case - as it costs nothing to tell them and if they have a record of it, they can't refuse a claim in that event.

[spider]

I'm assuming you're in the UK ? If not the regulations will vary *enormously* in other countries.

Regarding construction / use regs, I would (please bear in mind, I've not looked this up I'm working simply from what I feel is appropriate to post) :

1. It must be sound and not holed where it should not be
2. It must be securely attached and mounted in suitable places
3. It must not be in contact with other parts such as the fuel tank ( ! ) or brake pipes / lines or bodywork
4. It must not extend beyond the rear bumper area, pedestrian safety issue really here
5. It must not emit excess noise
6. Don't forget to tell your insurance company

Using something like a um 'scaffold tube' for the underneath 'run' of it I think is forbidden due to in an accident it would not 'fold up' and could become a fatal javelin upon entering the car.

Common sense really. As I say I've not looked into this, this is merely my thoughts. Others may be able to add more information for you.

[hayabusa1300r]

As above, Design and use regs apply also I believe, if you modify in anyway from the manufacturers design and installation you must notify your issurers. This applies to any mods including wheels, arches and the like