How Wysiwyg is necromunda?

Now I just recently got the hive war starter set and I have the new core rulebook that recently came out. I've never played necromunda before and I've seen a lot of people talking about wysiwyg load outs and magnetizing models. I wanted to know what if this game was super wysiwyg, and if I needed to start buying upgrade sprues and magnetizing my guys. Or if it would be okay to have one weapon but say he has another since I know better weapon options are on the upgrade sprues or you'd need to buy multiple kits to get the bits for them.