I've no backbox whatsoever, the sound is much louder than a standard XKR-5.0 at start up, when I hit the loud pedal and @ WOT, but no drone at M'way cruising speeds.

That said I may just have gotten used to the noise as my old XK8 was louder courtesy of straight through pipes and no catalysts whatsoever from 2007-2014, now that set-up did cause the neighbours windows to vibrate a little if I gunned it. Not that I did it often, but most of them were miserable old ******* that wanted a quiet life and resented me driving (what the considered) a posh car. My new neighbours however have two harleys and a 2010 dodge charger RT (no accounting for taste) and regularly comment on how sweet my car sounds

Here in the UK there is currently no noise pollution legislation for cars, but that may change according to the article below:

https://www.gov.uk/government/news/n...e%20the%20law.

Also at our annual MOT time here in the UK your car is 'supposed to sound stock' which they can only verify if there's another XKR in the place at the same time which has never happened yet...plus I've not met an MOT tester that wasn't a petrolhead. Most ask me if I'd mind if they can rev the engine when it's in the bay and always have a BIG grin afterwards

 

Replace the rear resonator with an X-pipe and delete the back box if you want a truly aggressive sound.