Can I raid 0 these two drives?

probably. more than likely just an increase in cache from 16 to 32 or sataII to sataIII, if that at all. i think controllers are more tolerant to differences like that as opposed to a capacity difference. dont quote me. ive always used the same models when ive raided. if your running an Intel chipset i would feel more confident, but again, dont quote me. at worst this will be a lesson in raid setups for you - i.e. plan for it and buy 2 at a time. hope that helps. you could also try google'n to find any data about the differences. good luck.