I have both the 86 300SDL and the 82 300TD. The SD IS a luxury car. Size is bigger. And the rides is smother and quieter. More bells and wistles. So understand that your going from a luxury level of car to the bottom line during those years.
The SDL we have, yes I know there is a difference between the 6 cylinder and the 5 cylinder SD, has some nicer things. Wider seats, electric seats, more soundproofing, rides as a heavier car, nicer sound system, etc,etc. The TD is a utilitarian car, No electric seats, or memory seats (yours probably does not have these) sound system is OK, not as wide or as heavy. A little bit noisier, due to the weight and lack of insulation. The ride is a little stiffer in the TD. and the rear seat room is less then the SD.
But you have the rear storage area. I have rebuilt the suspension to improve the ride. And will go thru the car cosmetically to make it a nice vehicle to own, New carpet, seat covers, trim etc. and a new Cd indash unit, Will redo all the wood trim and make it more like a new car.
I truely love the SDL and the TD. But they are different beasts!!.
You can enjoy the TD just understand that it is a step down on the totem pole of luxury.

Dave

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1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car