Please allow me to add an extra remark.
When you buy an unfinnished product you can't tell what part was unfinnished. Was it software, was it hardware?
There must surelly be a reason why the product is still not being officially sold.
You might believe it is something related to software, and that in future updates your machine will be just like any other, yet you should keep it mind that it might well be something slightly worse. If the reason is hardware, no matter what updates you throw in, your machine will never be like the ones approved for releasing.
Keep in mind that the products being already sold in unofficial shops, if they were not subtracted from the production line, they were probably supplied for evaluation to someone that was aware, opposite to your final consumer convictions, that they were getting hold of a product that is very likely to be far from what should be expected by you.
These, lets call them testers, don't intend to keep the produtct as you do, because they will get the final version for sure, in time.
So, please follow the advicing given so far, and be patient. The wainting is for our own good.