I have a K&N intake with a cone filter and an edelbrock manifold. When the car is cold the intake is nearly as loud as the exhaust. As it warms up it does get quieter but when i shut it down it makes a noise almost like it is exhaling. Is this normal? Do I have a leak somewhere?

 

Your intake is louder with a cold engine because your air/fuel mix is richer. And it's not uncommon to hear an "exhale" sound when you shut down. What you're hearing are normal "engine breathing" sounds that the stock air box muffles out. Nothing is wrong.

 

also the idle is higher when the car is cold so that may be the reason as well.