Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
As far as I know, there should be no difference in performance between the two - however, the R360 core should have the heat sensor and all that jazz, which the 9800 Pro (R350) does not have. I've heard that almost all the Pros with the 360 core overclock hella high - and rightly so....
Recall that the 9800 XT was basically just a higher clocked 9800 Pro with a thermal sensor (for overdrive ability) and more onboard memory...