First year of the 104 was 92 in the 2.8 300E I believe (? not sure)
Last year of the W124 was 95.
Personally I would get the 103 if its in good condition and near 100k
Mainly, because in the later cars, ASR is a pain when it goes bad and the engine harness problem can cause serious issues. But if these problems have been dealt with and certified in the one you are considering then the later 94-95 W124 is almost a perfect W124.