What needs to be replaced? If it's steering and suspension parts, many of these parts are exactly the same on a 190 and 300. And one could logically argue they will last LONGER on the 190 because it's lighter. And if they're the originals, then I say 160K miles is a pretty good run.
I should qualify this by saying that I have a '92 190 (2.3), and I chose it over a 300. I just like the smaller size better. (How un-American of me.) The 300 just felt much bigger, and less nimble to me.
The 2.3 is certainly no speed merchant, but it's adequite for my driving style -- admittedly, my wife says I drive "like an old man".
Just my humble opinion.
'92 Mercedes 190E/2.3 (247K miles/my daily driver)
'93 Volvo 940 Turbo Wagon (263K miles/a family truckster with spunk)
'99 Kawasaki Concours
'85 Jeep CJ-7 w/ Fisher plow (226K miles)'93 Volvo 940 Turbo Wagon
'53 Willys-Overland Pickup
'85 Honda 750F Interceptor
'93 Nissan Quest
'89 Toyota Camry Wagon
'89 Dodge Raider
'81 Honda CB 750F Super Sport
'88 Toyota Celica
'95 Toyota Tacoma
'74 Honda CB 550F