Just a couple of things to add but first, I don't begrudge folks who try to make a few bucks selling kits. But the buyer should understand just exactly what it is that he is purchasing
The system for 999 EURO is $1390 in US bucks. The system comes without a prepump and without a HP pump unless I misread their advertisement. Further, the HP pump is advertised as an inexpensive pressure washer pump which means it most likely is brass. Nothing wrong with brass as I see it. In fact, that is what my pump is made with BUT brass should be flushed every time it is used.
Beyond those comments, you're on your own.