My experience with the standard brakes was fairly dismal to say the least.
Car is a 32 GTR, running standard brakes, with air deflectors and 180awkw. The standard rotors just got to hot (only ever did four laps then a cool down) and continually managed to destroy a set of front pads every track day. (they were QFM race pads not sure what type). They are way understized for the weight and speed the car is capable of. So after much debate (the car is purely a dedicated track car, only driven on the roads to and from events) the decision was made to grab some 6spot ap racing calipers and 365mm rotors. Unfortunately i have not yet driven the car on these yet as it has been in the shop being treated to a few nice engine upgrades hoping to pull out 300awkw, so will let you know how it goes.
But please dont skimp on the breaks, they with suspension and tyres are the most important parts to a car. Spend the money if you can, and im sure you will never regreat it especially with the power you are aiming for!
good luck!