All our 206's have range extenders fitted which gives you about 3:15 with a little reserve. Our 205's get about 1:50 with standard tanks but with the 44gal aux tanks fitted it's about 2:20 which is far more useful a range ( plus you can still use them as seats!).
I managed 3:30 in our AS350 up at 9000ft doing 60-80 kts on border patrol in Macedonia (good job the seats were comfy, I wouldn't like to do that in a 206
)