The polini kit is awesome. Installs in minutes. Specs say it increases hp from stock 1.9 to 5hp. Add a bigger carb and an expansion chamber and you'll get even more.
When I first built my bike with the stock V1, it went about 25mph. Ported the stock cylinder and got it to 45, but it had no bottom end. Just chugged up to speed. Totally sucked on the track, and couldn't even compete with the china two strokes.
After adding the kit, it screams. It blows away the ktm clones and the morinis, and is probably the fastest two stroke at the track (not counting the moto-peds, but they have gears and cost 10 times more.)
I raced with the moped guys and it was one of the top five fastest bikes on the track.
And I've got plans to make it faster. ; )
Hills will be no problem. And yeah, treatland is the way to go.