On Radio 4 just now the company providing them said they picked up those noisy exhausts that pop & bang. Surely they look for a dBA number.
Pops & bangs if quiet enough aren't illegal
We have an annoying local lad with a tweaked up old Golf. He must burn more fuel on the pops, bangs and crackles than pushing the car forwards. You can here him coming from next village. A good candidate for above.
