both vehicles have their own common issues, both severe and trivial. It's tough to say one is inherently better or more reliable than the other. D2s are known for catastrophic engine failure due to slipped cylinder liners (yes it happens more often than not) where D3 has a totally different engine. if you can avoid/repair the engine, the D2 is probably a great bet, but with that big (expensive) question mark, there's no clear answer.
just know that either purchase will result in joy, anger, pain, and financial expenditure.