It cost me a fair bit more than $3500, but for what I've achieved - it's been worth it.
The minimum $3500 I was referring to, was to purchase a RB25det front cut... and get the complete Engine, Loom, Computer, intercooler etc, then drop it in...
I didn't consider slapping a turbo onto the side of my RB25DE, as I wouldn't have been able to gain the power I was after. You'd struggle to make more than 160rwkw safely with the 10:1 compression, on top of that, there are also the limitations of the RB25DE injectors and computer. In my opinion you'd be far better off buying the turbo car, and gaining all the good stuff in one hit, than trying to dodgy up a turbo conversion.
If he sold the R33 GTS for around $12,000 - then purchased a R33 GTS25t for $16,000... He would have gained a RB25DET, loom, computer, intercooler, bigger brakes and wheels, five stud hubs, LSD etc... for $4000.
And you wouldn't have to worry about getting booked by the cops for having a turbo conversion on a non-turbo car... not to mention the insurance trouble you would have on the modified car.