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.
I've got the same motherboard and case and they're doing great together. As far as aftermarket heatsinks go, the Thermalright Ultima-90 just barely fits in the case if you want to do some serious overclocking.
I bought my Ultima 90 from Silicon Valley Compucycle. Great service and speedy shipping. :)
Ultra 90:
http://www.svc.com/ultra-90-k8.html
Ultima 90:
http://www.svc.com/ultima-90.html