I have 07 gs350 awd with vossen 20" wheel without any suspension

now im having a problem with rear side of my car it make rubbing if someone seat back there..

so if i install lowering spring
it may fix that problem ?

 

no. im assuming you have incorrect tires on the car, possibly over spec'd which is causing the rubbing

 

i have 245/35/20 and 275/30/20

 

What offset are the wheels? Lowering will make the rubbing worse. Your problem is your tire size.
Not only they're >3% larger in diameter than your stock. They're also ~1% difference from each other(front/back). Getting the diameter as close as possible in AWD is important.
I advise you change the tires and use this calculator to select a better size.
http://www.1010tires.com/TireSizeCal...mp;vehicle=yes

 

^ correct. I mean you could use that front tire but i dont recommend it but even the overall diameters of those 2 tires dont match

 

o...my,.. i just installed nf210 on awd with vossen 20inch.. still rubbing!' T.T help me guys..

 

if is the tire problem then tell me the size please

 

Who sold you the wheels? Maybe they can help you with offset specs. I know we've been trying to help you with tire sizes but knowing the wheel specs would really be helpful.

 

if anything lowering the car will make the rubbing worse.