ADPearl3GS

I know this has probably been covered a million times, but I can not find anything specific. I am looking at picking up a set of staggered wheels for my winter set up for my 3GS AWD. Here is my question, what tire sizes should be installed to keep the rolling diameter the same and still work on the car correctly.

Wheel Specs: front 19x8.5 +18 rear 19x9.5 +21

Any help would be appreciated!!

Duonghtx

iTrader: (1)

255/35/19 rear , 225/35/19 front. Thats what i would do.