Decisions on a 300D...

[MT_Merc]

I guess I should introduce myself first. First, you can call me Will of you want to instead of the username. I'm a Senior in college majoring in math just for a general degree; I've always loved things mechanical, however, and may end up doing some kind of automotive work when I graduate.
I was originally going to fix my Dad's original but worn out after something like 350,000 miles, 300D (we don't know exactly how many miles it has, the odometer broke at about 268K long before it finally quit). I ended up buyin my Fairlane because of the complexity and expensive parts associated with repairing a Mercedes diesel. The good on this car is that it is a relatively rust-free car (some floorpan rust and driver's fender are the only issues there), the body is 95% straight with just a few dings here and there. To my knowledge it has never been in a major collision although it was hit in the driver's door and repaired and also had to have the frame aligned a couple years after we got it. All of the glass and trim is intact with all but a few pieces in good condition. Basically, although the interior needs to be redone and it needs paint and some bodywork, I think the car is sound and in easily-restorable condition. The suspension and brakes probably need to be gone through, but there are no missing or broken pieces.

The area where I am really wondering what to do in is the engine. After it quit it was half rebuilt with the head reconditioned and a remanufactured injector pump was installed. It failed to run after that, and I now think it may have been because the injector pump and possibly cam timing was significantly off. What I want is a turbo. I know you can't make a five cylinder diesel put out huge amounts of power, but I'd want something more reasonable than the original 80 or so horsepower; maybe something like 130. I would probably be looking for a turbodiesel motor to swap in and probably modify (a little more boost and possibly intercooling) except that the current motor has something like $1200 worth of parts in it. Is it possible to properly turbocharge the original motor or am I looking at finding a different motor? I would like to use what I have and do whatever modifications and custom work I have to, but if that's not possible or not worth the trouble then I'm willing to accept that. I do want to get this car (which my Dad bought in '86) back on the road, but I would like more power and am willing to take the time to do things right.