I would do some research on this car. Do a search on this web-site and you may find out that the 91 and later 300SD has the dreaded 3.5 "rod-bender" engine in it.
I hate to bring the bad news to you, but watch out for these motors.
Here are some links for that info.

350 SDL

1994 350SD Purchase Questions!

350 SDL Engine

I hope this helps.
ARI