fitting a decat pipe will not make any real difference to the sound although it should improve performance slightly. you would need to fit a good stainless steel performance exhaust from the likes of scorpion or powerflow to get the best sound and performance from it.
what causes aknocking sound on mazda T35 engine when its running
extreme cold temperatures might cause Mazda rf diesil to make knocking sound , however; it is recommended that you get it checked from the mechanic.
Returning, or capable of returning, sound; fitted to resound; resounding; echoing back.
Could be the brakes are metal to metal.
take it in and have one welded on cant beat the sound and quality....
I don't know, take your car for a check up and tell them about it...
Replace it.
battery is low. get a boost or charge the battery.
The sound may be caused by a worn or stretched belt. Ask a trusted mechanic for his opinion.
It is in front of the radiator and the horn itself can be bad.
The walls of expensive chambers are fitted with foam wedges. The sound goes in and cannot come back out. Egg cartons, Blankets with form rubber behind them all soak up sound. A (not recommended) thin sheet of lead will work also. Sound hits it and does not bounce off it very well.
I had this issue with a Honda accord, the sound may be your CV joints and not the wheel itself.