Just want to see if anyone ran a square setup on the 21+ is350 model. I got a used set of wheels 20x9 +38 on a 245/35/20 tires. Will running this square set have any issue with fitments? When I tried using the wheel-size website it's not really within the overall diameter than the OEM. Will this cause issue? Thanks in advance.

How much is it off from overall diameter? It should be close, forgot what percentage but if it's too off, the AWD light will go off. Just eyeballing it your specs, it seems like it'll be ok.

From what I see on the website front overall diameter and Circumference is gonna be 5% larger compared to the OEM wheel. While the rear overall diameter and circumference is 1.4% more compared to the oem wheels.
OEM Front: 235/40/19 19x8.5+45
OEM Rear: 265/40/19 19x9.5+60
Square set up: 245/35/20 20x9+38

Thanks in advance

On the back you won't have any problem with that setup, but the front i might be a problem with 245mm width tire, it might hit the control arm, I am running 20"x9" with +38 offset up front and run 235/35/20 and the back clearance only 3/4 of an inch from touching the control arm, if you run narrow tires, should able to run 245/35/20 up front

Thank you for getting back to me. What is your current set up? When you mean back clearance did you mean it will rub on bumps and full turn? I hope it doesn't cause any major issue.

I am running on vossen VSF01 20"x9" +38 and 20"x10.5" +45 and 235-35-20 and 275-30-20 out back, these set was on my 2nd gen IS350 it's was perfectly flush on 2nd gen IS, but the rear track of the new 4th IS is wider than the old IS, even with these same set up the rear on my 23" IS poke out about 1/2 inch out the rear fender and the front sit perfectly even to the fender

Only pokes out 1/2 inch?

OEM is 235/40 and 265/35, the overall diameter is the same front to back in OEM form.
​​​​​Those tires will be 5% off, normally, you should not go past 3%

You'll never have an issue with the AWD system if you run a square setup, since the front and back tires will be exactly the same.

Is there a solution to bring it back to close to 3 percent? Does adding spacer to reach the oem offset will help with the over diameter? I don't really want to spend any more on tires. Thank you

The tire diameter is essentially how tall the entire wheel and tire are. Offset doesn't really matter in this context.

If you're running a square setup, it'll be fine.