Boost issues
 

I just bought a 2000 S4, and It's not going into boost. Any ideas where to start. The guy who sold it to me told me that I had to fix the leak in the exhaust, and that would solve the problem. It does not make any sense to me. I know you need pressure in the exhaust but correct me if I am wrong. A exhaust leak will not affect the car going into boost. HEEELP!:(