There is plenty of information that can be found via a search on here.
But basically not worth doing. Cheaper, and more effective to sell off your old N/a (maybe get $1500 for it), and get an RB25DET (maybe $2500 for one).. and swap the whole engine over.
If you did turbo it, due to different compression, etc you would only be able to run fairly low boost levels (7psi or so). It would work, but if you got that far, you'd probably want to modify it, and then you may as well have got the RB25DET put in instead.