The ones posted on that (crappy buggy) website, look like they are just tapped holes in the ally... in which case you are worse off strength wise than a steel bolt into a steel hub.
I hope you don't mean the website i've posted
The ones i've got (text from the website):
By the application of a very high-quality special aluminium-magnesium metal, pressing in the threaded inserts is unnecessary.
They are +-100£/set of 2.