really not worthwhile unless you are super keen to get your hands dirty yourself. By the time you have gotten everything, paid someone to put it all in, found the 5-6 things that weren't right and bought the right ones, upgraded all the things that wont be up to pa (the brakes), decided you need a 5 stud conversion, etc etc. You will have been able to buy a turbo for 1/2 that and in 1/10th the amount of time. So yeah unless this is a process you want to experience.. don't .
and RB26 is just multiplying the problem more because you are talking about an engine that really wasn't designed for the application. An RB25 would be more sensible, but really.. just buy a gts-t. Enjoy that until something dies.. and then think about engine swaps imo.
At a rough guess. Paying someone to do it it, and get all the way up to the same car as a gts-t. 5K+?
Paying someone to put an RB25 in. 8K+?
Putting an RB26 in. Lots?