Hi,
to be honest I think those ballscrews look the part.

I posted much earlier in this thread that linear components, and ballscrews in particular are the heart of the machine and good quality components are unaffordable new in most cases,
and that second hand or new old stock are really one of the few cost effective means that cash strapped hobbyists can get true quality parts.

Those German made screws are DIN P5, I would be pleased, even proud to have them in my machine. Those LGH linear rails and cars are OK too, they have four rows of bearings,
two on each side, an upper and lower. The sketch of the car might rather look like there is a single row on each side but that is deceptive.

In any event linear rails and cars are expensive new, but still very VERY much less than ground C5 and C3 ballscrews. If you can get good ballscrews, say new old stock, but bought
new linear rails/cars that would still be a good deal.

Downside is you take what you can get and design your machine around them......not design the machine and then try to find the parts. That would be fine if you bought
new parts, but now that you are acquainted with the cost of new parts you probably realise that they are prohibitively expensive.

Craig