Thanks Rich.
Yesterday night, i did cable management a little And i also reverse the back fan so the air is sucked in the case, then I added 2 x 120mm USB fan Just stick to the 3 x blower-type cards i had. Finally i removed the filter+the plastic shroud at the front And i left the front closed and locked. Ran That all night long and now gets those temps (i think its fine) : 65/63/52/64c
PS. I should have bought 3 non-blower since they run 10C+ lower!
Now, i feel it is safe to go install my 4U server at a serverroom That got A/C and is secured. The wife will be more happy to not ear those fans anymore

Pics (i have a L4000):
http://Goo. Gl/photos/nuvTUS9yocMC9rL4A
Remove the space in url, it gets flag as suspicious!