How much lower if at all is the ISF than the IS350? They appear lower but I can't tell because it could be the illusion of the much bigger wheels.

 

From memory, I am inclined to say the ISF is only 1cm lower than the IS350/250. Can someone else confirm that?

 

OP, I see you're from Boston, if you'd like to see it person just let me know. My ISF is stock height.

 

I doubt the AWD versions would be close to the ISF in height, maybe the RWD cars are closer.

 

ISF sits 1 inch lower than the regular IS models

 

I appreciate that man. Thank you. I was hoping on getting factory measurements on ride height because I'm trying to buy bigger tires for my IS350awd. I'm a 25" outside diameter for my factory wheels, with factory ride height, and I learned from another thread here that ISF's wheels have an O.D of 26" and they're getting away with it without any rub which gave me the idea that I too could roll with 26" wheels... and then I remembered that the ISF's I think were lowered... Leading me to believe that without lowering, I could get away with even more outside diameter, right?
My goal is more sidewall, with a touch more width to protect my rims from curb rash. I want the max sidewall because I like smooth gentle rides, and the roads that I travel aren't in the best condition, so more sidewall will give me a touch more pinch protection when I hit the inadvertent pot hole. The local tire place said the tires I'm running now (235/45-17) are the biggest my car can handle, but for some reason I'm not buying it, which prompted me to ask the guys here that actually run bigger tires. My only concern's that the ISFs run a modified front wheel well insert for more clearance, which I'm hoping they're not.
So if the factory ISF is 1" lower than stock, I see no reason why I couldn't run at least a 235/50-17. Does this sound logical?

 

IS-F also has different knuckles on it that push the wheels out further toward the edge of the fender in the front.

 

Forget about the ISF and focus more on IS350. I owned a 2008 IS350 prior to me purchasing my 2011ISF. So I'm familiar with the car, my 350 came with OEM 225/40/18F & 255/40/18R that put rear tires at just over 26in OD. But if you go with 235/50/17 You end up with OD of 26.25in with sidewall height of 4.63in. That over 1inch taller than Your original tire size. Or go with 245/45/17 that will fit and you 25.68in OD with sidewall of 4.34in but leaves closer to your OEM tire OD. Difference between those two tire sizes is just .31. Also remember when you go up in tire size you will be changing the speedometer reading, gearing and additional up sprung weight since you're going with a larger heavier Tire. And if you still want to go with the 235 50 17 if memory serves me correct there is a pretty big wheel Gap between the top of the wheel and the top of the fender I'd Hazard a guess to sing at least 2 inches or more. They may just fit but aesthetically that's a pretty hefty Tire.

Here's a tire size calculator breaking out all the information you need

 

Oh yea totally, I have all that figured out. I'm on a 235/45-17 now, and want a tad more sidewall still. Just trying to figure out what others have ran in the past so I can see what's up. Thanks for all the replies thus far guys!