For all of you who are a little bit leery. The Razorback is not a kite which will kill you nor is it a kite which is only for speed cracks. I've had a close-to-production model which you can see on the photos (the yellow-black one) for testing.
The price, which is not really cheap but justified. Look at all the details then you can evaluate how much time it will take to build one.
I have a lot of fun with the Razorback because it is not only very fast it can also be very powerfull when wind is over 4Bft :-)
As AE told you why using skyclaws it is also better for starting the kite. It needs to be pulled very consistently to start. Pulling to hard or pulling little bit harder on one side you will never get the chance to start the Razorback ;-) so you can dose better with skyclaws
In fact you have to be fanatically assessed in speed or powerkites if you think over to buy one.
Here is the link to my test report http://www.drachenforum.net/forum/Razorback-by-Level-One-Kites-e954291.html
(sorry, only in german!)