I am shopping for old Mercedes but wanna make sure l understand what each of these different model types mean.Please provide specifics in terms of features for each if possible.Thanks!

300D is a turbo diesel sedan (123.133)
300 TD is a non-turbo diesel wagon (123.190)
300TD ''turbodiesel'' is a turbo diesel wagon (123.193)
hope this helps, l agree they r confusing

l am going to clarify something for the answer below.

There was never a USA model W123 called a 300D-T
No early (up to 1981)300D sedans (123.130) have a turbo
ALL later (1982-1985)300D sedans (123.133) do have a turbo
The moniker ''300D T'' is a slang term to distinguish early from late, no car was actually called D-T. This is just an easy way to say ''later 300D''

If u were looking for a W123 sedan without a turbo from 1981 onward ur only option would be a 240D (123.123)

Veeeach is absolutely right (read his answer above mine.)
Just one more thing: I've seen 300TD Turbodiesel wagon called 300TDT in some books on Mercedes cars, but l think it is not ''official.''
By the way, l had an '85 300TD Turbodiesel wagon (lost it in a stupid accident a month ado) and it was a fine car. Very dependable and functional. Go for it, you will like it.

l hate to correct people but
the 300 D is a Diesel sedan
the 300 TD is a Diesel wagon with a turbo
the 300 D T is a Diesel sedan with a turbo,

the base engine in all three vehicles is the same, with the exception of the added turbocharger.

All three r very reliable cars, yet, given the age of them & given that u have the choice opt for the standard 300 D - yu dont have to worry about a turbo replacement.

l hope this will help u in chosing.

300D An absolute slug,no turbo no power,300TD turbo has good power good fuel economy,300D-T almost the same vehicle as TD the newer you buy the more emmission control systems they have. l drive a 300D turbo goes like a scalded cat good off the line it is not going to spin the tires,top end well l have had mine upto 110 MPH ran out of road,34MPG.The only other difference is trim packages out side and interior

The T indicates it is a station wagon.