YES! If you want the full potential for handling you will need 17" or 18" rims and tires. If your into the ralley style look at Year One for the new 17" aluminum rally's Then look into Falken 615K for tires. ( that's my plan for rubber when funds allow).
I just got back from the Autocross at Carlisle and tires were my biggest handicap . If your going to all the trouble, time , and expense of changing out the suspension and then getting BFG t/a's you might as well have stayed with the bone stock set up.