This is a little tidbit about how I connected the components in my first crossover. 

I initially used ring loops at the end of my crossover components and used a steel screw/nut to attach the ring loops together. This way I would be able to swap components as needed after assembly. There was a nasty harsh timbre present overall, but especially in the tweeter.  A wise man told me to use brass screws instead of steel screws when attaching the ring loops. He insisted that steel screws were magnetic (ferrous) and therefore would act as a small inductor in the signal line. However, brass screws are non-magnetic (non-ferrous), and therefore would not act like an inductor in the signal line. He said the difference would be most noticeable in the highs such as the drum hat, bells etc.

This seemed like snake-oil, but I tried it.  I purchased some brass screws from the local hardware store. The brass screws and nuts cost about 12 cents each. I installed them.  The difference was immediate and obvious. I didn’t even need my wife’s ears (hers are better than mine) to discern the difference with this one. The tweeter smear instantly cleared. Highs were crisp and clear. Metallic things sounded metallic. Violins sounded like string instruments. The difference was big! The brass screws made about the same improvement as replacing my Kenwood amp for a Bryston. So, if you decide to use ring loops and screws to connect your crossover components use brass screws!

I have recently noticed that the nuts and flanges on most terminal cups/posts are ferrous.  This is bad too.  I haven't tested the difference between 1 ferrous nut and 1 brass nut, but I convert all of my cups/posts to brass nuts with a non-ferrous ring loops.  I am sure there is a difference, but it is likely very small.  Perfection is often in the small details and a 12 cent screw and nut are darn cheap.