You should rotate wheels as a standard part of car maintanence, as long as all 4 are balanced there is no further work to do, just swap them, also when swapping, put say the front drivers onto the rear passenger so all parts of the tread wear evenly.
For the exhaust try 1st thing in the morning when its cold, may actually see where its leaking then.
Tire rotation incase i didnt type it too whell 
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=43
