$100 is an excellent price, just be sure they aern't damaged and are genuine ITR cams.
If you put those in your GSR, you'll need an ECU tuning system. And if you want to rev past 8000 you'll need a set of ITR intake valvesprings. You can move your GSR intake valvesprings over to the exhaust side, because GSR intake springs = ITR exhaust springs. Then you can safely rev to 8400.