After 30+ years riding and racing...these are sooo mucch fun! Here in Vancouver BC the season is not long, but lots of roads perfectly suited to the hooliganism of these bikes.
After R1's and such I committed to the KTM 640 Enduro which I am converting. There are loads of excellent sites for parts in Europe, the UK having some great ones.
After pipe, carb, Talon wheels, wave rotors, cam and assorted other goodies, I am into it (bike and parts for about $12k Cdn)...or about 500$ US. Anyhow, this will give me around 62 HP with no discernable reduction in reliability or longevity for the motor etc. It will also be a ripping dirt stead with its knobbly bits on.
With another 1500$ and a reduction in reliability, increase in maintenance...I could get 67-69 HP, but if you are going to use it as a daily bike as well...
The factory set ups are 70+ HP!!! at 112 Kgs- too much fun!!
These bikes are the future for sure as it gets harder in every jurisdiction to really use and enjoy 150 mph sportsbikes. In BC you can go to jail easy for those speeds so...why bother! You can have just as much fun with less risk from the Mounties.