thx for the comments

and thx to Maxwell for the results
I'll re-render with the same settings with my new config (must wait 2 weeks)
Render time/Noise really comes from plants cause i made tests without them, and having better results in less time (with diffuse Mat)
Here is another cam, just deleted the car and plants :
original size 1539 x 2048
render time: 11 hours 33 minutes 41 seconds
sampling level reached: 14
XP2400+ 1,25GB DDR266
