What's the reason for them being "illegal"?
Well boss cops we hae plenty of around here, and understand if you're asking for it you'll cop it (ho ho) and that's not a drama. Just find it hard to believe they become "that loud" from slip ons...
tail tidy doesnt meet the adr rule
pipes dont meet the adr rule of noise
in nsw to be honest either arent too much of a drama
other states have problems with the above
like anything you roll the dice and take your chances