20" specs help

i have a 06 gs.  what are the specs for some 20's?  i want it flushed to the fender without fender mods..an little stretched tire would be fine.  i was hoping to run 245/35/20 front and 275/30/20 rear.  thanks.  btw, the rims im looking to get are the wed kranze borphes.  does anyone have any?

[url]http://www.weds.co.jp/products/kranze/vishunu.html#[/url]

click on the GS300 or just click on each wheel on the wheel products and find a GS it will show the specs

thanks.  but are the wheel specs clear the 430 since the brake calipers are bigger?  and also, how do i know if those wheel specs are for non fender modded cars?