i noticed last night that there is a slight "click" sound when i manually shift, but only from P to R to D, not from 1-4. it's not the usual trans "clunk" sound, it's literally like a tiny little metallic "click", like 2 paper clips snapping against each other. is this normal? sorry if i am not being clear, but it is pretty hard to describe in detail.

Normal. Every Benz I've owned does that.

Noticed that today on the 95 C36 I bought last week, not only when shifting, but when driving too.

It also seems slow to engage Reverse, any ideas?

I actually stopped by my indie mech on the way home and he said the bushings on the shifter are bad, which makes sense bc there is a bit of slop in the shifter itself.