1) That's because the front intake panel is restrictive.
2) That side panel 92mm fan is "hurting" the air flow of the case.

side window fan with & without-

http://www.home.earthlink.net/~lazym...WChillvent.htm

Thats are possibilities I didn't think off. :)
Could it be that the dust filter from the front intake restricts it?

I'll test it.

best case I ever had was the default cgieftech dragon medium case. 3 fans in front, 2 of wich in a HD cage, and 2 in the back next to the PSU fan.
I had a lian li PC-60 that couldn't beat it's temps. (was easier to carry however, guess you can't have it all)

Equation to calculate air flow requirement in a case -

Q = 1.76 W / TC
Where:
Q = Airflow required in CFM
W = Heat dissipated in watts
Tc = Temperature rise above inlet temp ° C
For example, how much CFM air-cooling does a system need that dissipates or consumes 300 Watts, allowing only a 10 degree C rise? The above equation results in 52.8 CFM.

source
http://www.jmcproducts.com/cooling_i...e_analysis.pdf