Are you sure you're not looking at GVWR numbers?
1987 300E automatic - 3,219lbs curb weight
1987 200D automatic - 2,884lbs curb weight (euro)
1987 250D automatic - 2,976lbs curb weight (euro)
1987 300D automatic - 3,064lbs curb weight (NON-Turbo)
1987 300D automatic - 3,197lbs curb weight (TURBO)
1992 300D automatic - 3,384lbs curb weight (2.5 Turbo)
1987 190D 2.0 automatic - 2,513lbs curb weight (euro)
1987 190D 2.5 automatic - 2,844lbs curb weight
1987 190D 2.5 automatic - 3,009lbs curb weight (USA Turbo)
Source
http://www.automobile-catalog.com/specifications.php