With 32" tires on stock alloy wheels, you will be just fine. Your sidewall will be 4" wider than the wheel. Optimally, you want to be 2" wider than the wheel - as in a 15"x9" for an 11.5" wide tire. A steel wheel will give you some advantages on the trail, but, they are heavy, increasing your rotational mass, which in turn will increase your mileage on the street, and stopping distances. Keep the alloys, run the 32s, and have fun!
-Ken