90% chance they wont notice or care that your pipes are loud and obnoxious, 5% chance theyll tell you to take em off because the next fella who pulls you might not be so nice, 5% chance you get a small fine.
No chance of riding without insurance or perverting the course of justice or any of that crap, might get done for riding without insurance if you bin it and its your fault, but even thats a slim chance, odds are they wont bother because youve punished yourself enough.
Depends where you go aswell, North wales police are cunts and hate english motorcyclists (only english ones, my welsh mate rides like a knob, every time he gets pulled in NW, as soon as they hear his accent, they let him go scott free) so youll get done for whatever they can get you for.
Humberside are knobs too, but theyre better than NW, if your riding on the weekend when the weathers nice, on a sportsbike, you better not be speeding should you encounter a rozzer.
Cheshire police ive found pretty good, most of the traffic cops are pretty reasonable imo.
The rest of the country as far as ive encountered, the police are far to busy to bother with small traffic violations, merseyside doesnt even patrol its own motorways, cheshire does it for them.....