How important to fix???

I have an exhaust leak near the headers somewhere. I can hear it but i havent really had time to look for it since i havent been driving the car too often. it runs weaker than it used to but idk if that is just from the latest tune up. Could the lower amount of backpressure be what is making the car so hard to keep running???? I mean i've had to pump it quite a bit to keep it running...then it is fine. Well, how important is it to fix??? (im a cheapskate and am selling the car)

Lol, that is exactly my thoughts, too cheap and lazy. Most of my parts are homeade or gifts. I got my carb from a guy and it was never out of the box. it's a holley 650 4bbl. I have my chilton's manual but I never get a real feel for tuning. Its fine for awhile but then sometimes depending on the weather or how much i drive it the car will act up and be a typical female: tempermental!