While the OEM pads may be adequate, I can't, in good conscience, recommend them.
They may work fine for your needs, and might have worked fine for others needs. But until you get out there and start driving, you're not going to know.
There is nothing worse than have to leave a track weekend early because you are not properly equipped. Do yourself a favor and get the upgraded pads. I'd rather see you over-prepared, then packing up at lunch time.