Certainly not 'restricted' to 165mph. Reviews place its top speed around 165-175mph depending on conditions, wind direction, rider weight etc. etc. But Aprilia never actually limited the top speed, it is of course limited by all the above factors and the actual bike's power and gearing. The 2001 Mille only has about 115bhp at the back wheel so 165mph would be about right.....In comparision, the new Ducati 1199 V Twin kicks out around 180bhp at the back wheel and has a top speed of around 185mph. So the Aprilia has nothing to be ashamed of there!!!
Alter the gearing, increase the power and you'll increase the top speed, but for the rare times you'll actually do those speeds it would be far better to improve acceleration, midrange and torque instead.
