rear wheels are 18x9 monoblocks with 265/35 tires. what size spacers would you go with?

i'm thinking 20mm would start to rub. 15mm would probably clear.

car is on #1 pads and eibachs and already rubs on what seems like the plastic fender liner on deep dips.

 

try 15

 

i have 12 on the rears now and i wanna put them on the front and 15 on my rears... i have 235/35 19 inch rims...

 

theres a better pic on here for u too see ..http://www.cardomain.com/ride/3031995