The 'stance' of the vehicle will be solely determined by the suspension underneath it. If you want a level FJ, you can have one, you just build the suspension to achieve that. And then, you can go with a larger tire or stay with a stock tire.
I am personally running our Ultimate Kit on a 01 DC Tacoma, with stock 265x70's and honestly don't think it looks bad. Would new tires and wheels make the truck look better, yeah, but can I borrow $1500.
I'll will upgrade those later.
Hope that helps,