This is a heavily covered topic, so its imperative that you research everything you can THEN ask questions once you have a decent understand of what it will take. Here's the basic info to get you in the right frame of mind...
The harder you want to drive a motor, the more upgrades the internals need. A sporty engine can handle more than an efficient engine, like D-series'. Get an understanding of what your specific engine was designed for. Research what it takes to make a fuel efficient engine turbo-ready and whats a realistic goal for it. D-Series engines can be turbo'd a number of ways, ranging from upgrading the internals to keeping the stock internals but not being aggressive with it. Those that blow their D-motors usually run them hard without properly upgrading the internals to handle such vigorous driving, then wrongfully criticize the engine instead of the foolish owner.
