Help with new build

[wong93]

1) Intel i7-3770k Processor
2) ASUS P8Z77-V LX Motherboard
3) Corsair AX 850Watt 80+Gold
4) Gigabyte HD 7970 Graphics Card(3 fans)
5) intel 520 ssd
6) 4x4gb 1866 RAM
7) Cooler Master 212 evo


Above are the build I'm planning to get

1) Is it ok if i choose gskill 1866mhz as my ram?

2) If I plan to get another 7970 for crossfire in future,which brand should I get?? [There are only ASUS,Gigabyte,MSI brand] over here in my country

 

[strife_ff7]

Look at this http://www.tomshardware.com/forum/353572-31-build-upgrade-advice