Not to jack this thread any further but displacement has little to do with exhaust note! It's the number of cylinders, cylinder configuration, diesel or gas and the designe of the exhaust system. A big V-Twin sounds much different than an inline twin, as does a single cylinder on a moped? A formula 1 race car sounds amazing at maximum rpm and a NASCAR sounds like a POS Hillbilly open exhaust (which it is). Loud in our sport leads to getting banned from trails and closing of tracks. Unless your racing at a track then you should consider your neighbors, Stealth IMHO is the best medicine and one of the coolest things out there.