Fwiw, 18s will fit over your lower ball joints if you want to go really wide up front. I don't think that's the route you're going, but that's why I stepped up. I don't know if I made the right choice or not. As of late I've shifted my ideas from all-out autocross brawler to just actually running and driving big block car. It's less fun when I can't drive it :banghead:
I'd at least bump up to 15s for tire choice if nothing else. You can't really find wider than a 235 on a 14" wheel, and with a duster you can probably fit more than that (I'd guess 255s out back) before you have to move anything.