From experience I can assure you that getting into the 11s takes minimal cost. A set of 2530s and the normal performance mods such as air filters, full exhaust , cam gears, fuel pump and injectors can get low-mid 11's easy.
To get to 10's I made the move to go a single turbo setup with a larger IC, cam shafts, valve springs, bigger injectors, new fuel system (twin pumps), forged pistons, stronger rods, Autronic, new gearset, triple plate clutch and the above mods. Also, a set of Nittos helps the cause big time!! I did however leave the stock GTR suspension in the car as my Tiens are too stiff and give no rear end squat thus taking traction away.
Just out of curiosity, Munro, what clutch are you in your R33 and how often do you replace it? I managed to get 14 runs and some normal street driving done (500kms) on my triple plate Ogura before it packed it in and began slipping. I'm just wondering whether this is the lifespan of clutches when I'm pushing 450+ rwkw a the strip.