That is incorrect information they are slower. The reason that the 92 500Es are faster than later models is due to a computer which gives 322 vs 316hp. The reason that the 92 400E is slower is that it has 269HP vs. 275 in 93+ models. I think that this is partially due to a lower compression ratio of 10:1 vs. 11:1 for 93+ models.

From:

http://www.albeedigital.com/supercoupe/articles/0-60times.html

1992 Mercedes-Benz 400E 7.6 15.8
1993 Mercedes-Benz 400E 7.2 15.4

I am not going to suggest these numbers are correct but using a G-Tech I consitently get 0-60 times (when the air is < 50deg aka cold) between 5.4 - 5.8 seconds and this would be faster if I could get the car to not spin the wheels till around 30mph. I have done the quarter mile only a few times (and I am not confident in this result at all) in a low of 12.9 seconds and a high of 13.6 seconds.

Granted these times seem unrealistic but even subtracting .5 seconds it is pretty obvious that the 93 400E with 2.82 diff hauls ass.