I am curious about the major differences between the two and if one is better than the other with respect to the serious off road use thanks

 

D2 has more bells and whistles, but with that comes reliability issues, plus that darn tick, oil pump problems, half the radiator of D1, etc. Serious off road would require mod of either to taste and task at hand. I'll stick with the oldie, pass the Lucas please....

BTW 289,000 on 93 300TE, wish it was a diesel....

 

Read the tech section, this is covered in there.