I’m looking to get Black CS8’s for my 2005 IS300 I’m looking at going up to 18s from the stock 17. Because the car is Lowered and my front wheels are tucked behind the fender My worry is the wheels will rub because offset on the Stock is +50 and the CS8s are only 30+ I don’t want any rubbing and from what I understand the CS8s should poke out about an inch and a half more meaning I will have to raise the car which I’m fine with I just don’t want the wheels to poke too far out the fender I would like a flush look. Wondering if anyone here has any insight or advice that could help. Sorry I’m new to this lol

It depends also on the wheel's width, which you did not mention. Also, it depends on the tire size. Are the fenders rolled/pulled? If not, they could be made to fit to achieve a flush look with a wide range of fitments.

width would be 8.5 or I could do 9.5 with +35 offset if that would fit better. Tire size is also something i could use some advice on. My current size is 215/45

the wider you go, the harder to fit. Regardless, those specs will need some sort of fender mods to make fit is my guess.

I had <!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}-->18"x8.5" +30mm 225/40-18 front and 18"x9.5" +30mm 255/35-18 rear for my summer setup
and 18"x8.75" +20mm front and +35mm rear 225/40-18 for my winter setup.

It definitely needed fender modification.