i've found on my '01 SV that the Delkevic has the right balance of presence, noise & police tolerance.
It's a 450mm one, so borderline legal with baffle.
Give the bike a bit of power & it growls. It's enough to make cars aware of you when filtering & I've even had a police biker compliment the noise my bike makes!
The numberplate is standard but I've trimmed down the rear mudguard so it looks quite snug & tidy.