245-50-16 is it on the stock rims. I did. Rims are only 7" wide. That will put you 1" larger diameter (1/2" rim-to-road). You won't notice any power issues. You can go 245-45-16 to stay the same diameter.
Check these 2 sites for some more info.
http://www.discounttire.com/dtcs/home.do
http://www.tirerack.com