If you love the car that much and money is not a issue then go right ahead.
(BUT we are here to suggest to you that there is other options to make you life a little easier I guess...)
OPTION 1
The things you will need to turbo your R32 GTS will depend on how much boost you want to run. Here is a quick overall rundown...
You might have to strengthen the internals for example forge pistons. Then I believe you will have to alter the compression ratio, re tune/ new ECU / Dyno and fine tune.
Modify you exhaust manifold / fit a turbo manifold to fit the turbo
Larger exhaust
High flow air intake
Install an intercooler, make room for piping
New fueling system, injectors and fuel pump might need upgrading
Use high quality spark plugs
Use a different type of engine oil, one that is suited for turbocharged car, to what you are using at the moment to suite your N/A car
The car goes quicker now, you had better stop quicker too = Upgrade braking system, atleast to high quality brake pads. Also if you want, upgrade to larger disks and calipers. R32 brakes were never up to race standard untill the V-Spec II with Brembos.
You would probley start taking corners a lot faster = Upgrade your suspension, lower the car, install a strut brace so it locks the suspension towers to its maximum stability point. Upgrade your wheels and upgrade the tyres.
To put all the power at the wheels you need to upgrade your clutch and again depending on the amount of boost you want to run, you need a stronger gearbox.
You can't just pull horse power out of the air, something has to give (Give and Take) One thing leads to another. No such thing as cheap horse power.
OPTION 2
Source a RB20DET OR if you want, a RB25DET (for that extra 500cc you gain a bit more torque) OR a RB26DETT for a whole new characteristic type of car, from a half cut and do the engine conversion.
Atleast the engine work is done, its just a matter of fitting everything in the right place. As for the RB25DET and RB26DETT, you might have to modify afew engine fittings / mounts in order for it to fit probly. Make sure everything is welded in probley.
OPTION 3
Trade in or sell you R32 GTS and buy a R32 GTS-T or GTR