Assuming you could find models representing every possible permutation of the 1986-1991 S-Class in very good condition, what would be the best choice using the following priorities?

1. Ease of service
2. Power
3. Durability

I'm considering picking up an S-Class and am all over the place in terms of deciding upon which model I should concentrate my efforts. I live near the Poconos and don't want a car that will have to wind it's guts out to maintain a decent rate of speed on Interstate hills. Does this describe the 300 SE/SEL?

I would appreciate your opinion, particularly if you have experience with S-Classes of this era.