Weight and horsepower. 300SE is a little lighter which may account for it having approx. 10 more HP than the 300SEL.

There's a book titled "MERCEDES-BENZ Production Models Book 1946-1995" by W. Robert Nitske.

All models built from '46 - '95 are shown in this book along with basic info such as engine/transmission/gearing/fuel metering type/size/weight/HP, etc., etc.

Again, the weight, HP; rear seat leg room are the differences between the 1988-1991 300SE & 300SEL.

1991 was the last yr. they were built. That yr. would likely have all of the refinements MB ever put into this series of W126.

I've had mine for 7 1/2 yrs. and am happy with it. Not fast, but reliable.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"