unless u want a 10sec Drag car, else it's meaningless to drop a rb26 into a 180, which fxxk the balance up. For the $$ u spend, u could get a sr20 180 with HKS/tomei 2.2kit and a
HKS GT-RS turbo and makes it a very good all round 11 sec car.
u can't import a modded car now, but a lot of importer are happy to strip the car to standard and put every back after compliance. u have to pay for labour of course.
u might need a gts-t gearbox if u drop the RB26 in as GTR gear box is 4wd.
at least set of gts-t/gtr brake or even some aftermaket brake.
prepare to run top of the range sport tyre everyday, even R compound tyre.