On alot of pictures of cases i see that back fan is blowing out and fan down in front is blowing in... is that best way to set them up ? it did drop my mobo temp by like 2C but would it be better in other way around ?
It depends on your case layout. If the location of the rear fan is close to the cpu the fans could be fighting eachother compeating for air or disrupting the airflow through the case. It doesn't hurt to switch the direction of the 2 fans while monitoring cpu temps, just trial and error as every setup is different.