Any gear heads able to assist this amatuer? I have 3 concerns

[spree17]

I have a 93 190e 6 cyl:

1) After my running car is parked on my sloped driveway I notice 2 small thin lines of fluid. They are like 1 inch wide and 3 inchs long. They are parallel to each other. They are so small that I cant tell what it is. Any ideas on what they could be? I havent noticed any fluids being low. I had dropped some oil a while ago. Could this be the remains dripping from the that plastic guard/pan under the engine?

2) Yesterday after driving around 75mph my car seemed to vibrated via the steering column but it seemed fine at slower speeds. Today I dont have any of that shimmy or vibration. The car has pulled to the left just a tiny tad for 3 years but never had this high speed shimmy before. Is that a tire balance issue? How can I tell?

3) I dropped a wrench while working on the car 2 weeks ago.I think there is some sort of plastic guard/pan under the car that it dropped in to. Does anyone know how hard it would be for me to go get that wrench? Would it likely have fallen out on its own by now?

Thanks a bunch for any and all replies.