Has been done. Plenty of people running reliably turbocharged DE engines. Fact remains... If you can´t afford to put an RB25DET Neo in then you can´t afford to turbocharge your motor.
Have been through this myself. Planned for a long time to turbocharge my DE Neo, but when I worked out that it would actually cost me more to convert that engine to forced induction than to put a much lower km 25DET Neo motor in I soon changed my mind. Don´t fool yourself it is no easy task to turbocharge your car. It requires much custom work, many dyno hours and a lot of frustration. All equating to requiring much money. And after all that, what do you have to show for it? A high km engine rather like a handgrenade, very much limited in how much power it can make; incredibly responsive is really the only benefit...
Anyway, if you are really keen to go through with this, I found a lot of useful info in this thread: http://www.skylinesaustralia.com/forums/topic/33407-how-to-turbo-your-na/ You might find an answer to your question in there. 666DAN and N-DAWG were both very helpful to me; given that both of them have turbocharged their NA R34´s, they could probably provide you with the answer.