Do you know something I don't know? How/why would you reinforce any suspension parts? Looks like a very typical '20s-'30s era model kit chassis to me... frame rails, longitudinal leaf springs, solid front and rear axles. I don't foresee any need to reinforce anything. Yes, the tie rod is very thin (and to scale, it seems)... but even so I don't think I'd need to replace it with brass rod, if that's what you mean.
If you know otherwise, let me know.