Hi Craig,
Good choice, GTR looks awesome!
I didn't find it expensive at all for maintaining such a weapon of a car, close to 700bhp on stage 4, budget about £1000 / year for servicing. Pads and discs should last you 2-3 years, depending how you drive it and how much you drive it
Enjoy the car and respect its capabilities until you get used to it, it's a serious weapon