It isn't UNsafe, it just gives a little too much sway (tire roll) to the rear for cornering. The optimum tire size for the 17 x 9 wheel is the 245 45 17 believe it or not. Ford used that size on the Cobra R in 95. The wheel you have right now is what is making the tires look small. You might be able to get some "replica" wheels like you have now from someone like Diversified Products. Just checkout some of the people that sell "replica" R wheels in MM&FF then give them a call and see if they sell a 96-97 style Cobra wheel, just wider. ;-)