I have a 91 300SEL, And I have toped out at 159. But I had the chip removed, the cats cut out and the stock mufflers replaced with a pair of flow master 40's with dump pipes.
Did the same mods to 89 190E 2.6 and it tops out at 139. But on it I did side dump cafe pipes with a pair of 18" glasspacks, From 3200 to red line it cackles like an old Detroit diesel.