Yeah, number of cylinders does make more difference than RPM. Which is why we told the OP that the twins can never sound as smooth or wail like a Supersport 4-cyl at high RPMs. Ninjette at 14000rpms will always sound rougher than 600cc 4-cyl at same RPM. It's just physics.
I played golf at Pt. Mugu all the time when I lived in Santa Barbara.. right next to runway where F14s were taking off. They even gave us golf balls with F14s on them!
