G.skill Ares Series 8GB (2 x 4GB) DDR3 1866 can fit ?

It will fit and yes it's good so long as it is not costing you more then 1600

Yes, it will fit. Your mobo has DDR3 channels. However the speed is listed on the Motherboards support list (1866). Look for different RAM. You don't want to cap your RAM at a slower speed or it may not even be compatible.

Try this.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

i have now this one   but am looking for faster one

If you want faster 2133 is the way to go though you won't notice a difference between 1866 and 1600 you will only notice in benchmarks  

am just afraid from getting 2133 to get overheated or something

Understandable i use it don't have any issues but i don't have same motherboard as you do.