Get somebody that knows what an exhaust leak sounds like to tell you that you have one and LISTEN TO THAT PERSON... now how to tell if it's effecting your tune:
Do you have split BLM's? Then it's a good posibility the exhaust leak is before the o2 sensors. Here's how an exhaust leak at the EGR on the passenger side header looks in the datalog; The BLM's are higher on the "right" (passenger) side than the "left". The difference between the right and left BLM's gets larger during decel. There, now you know. Does OBD-II tell you where you're exhaust leak is?

 

OBD2 doesn't look for exhaust leaks, it does look for either bank being too lean or too rich, or if the o2 sensors are not switching properly. it also looks for problems with the o2 heaters.