The 140 engine compartment may be a little more accessible but the biggest difference between the two is the weight of the car. The S is lugging around about 1100 more pounds - aprox 4600 versus 3500, or about 30 percent more weight. In technical terms that's a lot. It clearly has an impact on both engine life and transmission life. And speaking of transmission the E320/124 is always a 4 speed while the S320 is always a 5 speed - 722.5 through 1996 then 722.6 in 1997. The .5 has a decent reputation but is an expensive rebuild whereas the .6 has a horrible reputation and is an expensive rebuild. I see that Sun Valley rebuilts are now the same price for a .5 as for a .6 - $2750 - the 4 speeds only $1250.