Well, I own Magnepan 3.6 speakers.
The connectors are the same basic steel, so what is the difference? You have a steel sleeve, to steel conenction to steel sleeve.
If it makes you happier to switch the middle part to not steel..??
I actually moved my crossovers next to the amp, and have bi cabled Kimber 8TC wires. Which coincedentally the eight bared ends of 8TC just fit perfectly (bare wires) into the Magnepan openings..
I have the later larger 'vertical' crossover box, with better caps in it than earlier 'flat' crossover boxes
You can easily open the crossover boxes and insert whatever favorite dampening material you want into them, and on them.
I used some 3M dampening material.
As for 'upgrading' the crossover, not me. i did that on a prior pair of speakers, and though it did improve the sound, it also made the speakers impossible to sell. So stock for me is fine.