I don't know about the significance of overdrive. Lots of new 4cyl cars still buzz at 3000rpm down the highway and they have to still meet the same standards of longevity as lower revving engines.
4 cylinders tend to have light pistons and rods which reduces loads on the bearings. 3000 rpm is nothing for a 2.2 and still turning 500 rpm less than my Duster cranking down the highway at the same speed.
