300TD vs 300D vs 300SD

[The Warden]

Okay, after perusing around the site a bit, I haven't decided which would wind up being best for me. *lol*

The single biggest concern to me is reliability. This is why I'm getting a diesel and won't consider anything else. I assume the drivetrain's the same between the bodystyles, so unless there's body-specific problems (haven't seen anything yet; dunno for sure either way), I'm assuming reliability's equal for both.

The second biggest concern is fuel mileage. I'm hoping for 30mpg. I would assume that the 300D, by probably a fairly thin margin, gets the best mileage simply due to having slightly less mass. I don't know where the 300SD and the 300TD would stand in relation to each other. Any input there?

If everything else was equal, my first choice would be a 300TD due to the extra carrying capacity (would need the 3rd seat), but with how rare they seem to be, I figure it's best to not hold my breath. Also, with the conditions I drive in, I'm figuring that a turbo's necessary...I have a feeling that a 240D or a 190D would be too underpowered for my needs. Also, luxury factors don't play a big factor...if the mileage was the same, the extra size of a 300SD would be nice, but that's not an important factor for me.

BTW, this will be a daily commuter, with about 250 miles put on it per week. At 14mpg, I can't continue doing that wiht my van...'sides, I've always liked the early to mid '80's M-B's. Also, any years to look for or avoid?

So, any thoughts? I'm doing a basic poll, although any general or specific thoughts/reasoning would be greatly appreciated. Thanks in advance!

{added in edit} Also, I wwant to shoot for a pre '87...an older car than that's more likely to fit in my price range (roughly $3K, depending on what my van sells for), and besides, I really don't want to deal with an aluminum cylinder head...that's one of the biggest reasons I chose an M-B over a Volkswagen...