I live in "light wind hell" (Dubai), where our normal conditions are 8 to 12 knots. We have dealers for Naish, Takoon & Cabrinha, but the Naish dealer carries all spares and has a small shop located near the beach. Due to the better dealer support 90% of kites are Naish.I personally have the X2 20, 14 & 8, weigh 84Kg and have the following twin tips 150X45, 140X40, 140X37, 145X34.
I agree that the X2 needs a bit more wind and is best with a fast board. Two friend have the 2002 Flash 5'5" directional and in 8 knots they can point higher than me, and look like they are faster (due to the spray).
But I get much more "Pop" for loops and from 9 knots can point as high as them.
The Aero 20 pulls more, but there is very little difference in the low end compared to the X2 20.
We consider 10 knots to be good wind and 12 knots is "STRONG" wind.