I think the question is really what is the biggest tire size. (period) with the shape of the front wheel wells, a lift kit will not increase the size of the space available for your tires.
I believe the max size you can get in there without major modification is about 29 3/4" total circumference. This is because the lower part of the front wheel well is narrower than the center. I think in fact, you might squeeze another 1/4" if you lower the car.
The big issue is the pinch weld that is at the rear of the tire less than a 1/4" behind the plastic inner well. It prevents you from modifying the plastic to allow a bigger tire. Some have ground it off and sealed it up to get another 3/4" of room for the tires but I am not really sure the value of that. I suppose it is up to you.