There are so many things that affect the exhaust sounds. Number of valves, valve arrangement, ignition timing, head design, compression and A/F ratios, length and diameter of the exhaust pipes and design of the mufflers are just a few factors. Me, I don't mind the way Harleys sound; I just wish there was movement associated with it. I will also have to say I don't care for the r3 at idle, but 2-5k cranking through the gears sounds freaking incredible.