245/50/16s are a little small and look a bit "off" on a large car like this.
255/50/16s are what I have on the rear and if you look you can tell it's smaller than the stock tires in the front, don't look too bad but you can tell.
245/45/16 would just be too small IMO.
I'd reccomend 245/55/16s or 255/50/16s, the former being stock diameter (well almost,) the latter being the widest you can safely fit on a stock wheel.