There ia design challenge for modern bikes because of all the emissions crap. Some manufacturers are good at hiding it, others very poor. The pipes on new Kwackers are hideously huge, and the silencers on the Griso and 1200 Sport are not much better.
I guess most manfacturers know that the first thing the new owner will do is swap the pipe for something lighter, and more svelte.
That may well have to stop if the proposed EU anti-tampering regs come into force.