I have an HS 3" afterburner jap exit fitted at the moment, straight through no cats and so on, its quite loud (static tested at 104db) a lot louder than most (the misses hates it! and asks me to switch to the track day exhaust every time I fit it!). But this is nothing next to one or two on here... Not saying any names "Simon.. and RCM Team ICE exhausts..."!
I do however not get any problems, either from neighbours or the police despite hoofing it past them when they are stationary just for fun!