Looks like 15 v 16 alone is good for about 20 lbs.
Tires depending on choice can be another 20 lbs. I am running Dunlop Star Specs 225/205, the Cup's are about 22lbs lessif I ran 225/50's per TireRack.com.
http://members.rennlist.com/911pcars/WheelWts.html