Intake Sensor
#2
I think you shouldn't listen to them. I'm assuming you have a 6th gen accord. These vehicles don't need a sensor that I know of for installing any intake system. They could be assuming that you have a Mass Air Sensor (MAS). This gen. accord don't have such a thing. It has a Manifold Absolute Pressure (MAP) sensor.
#4
I wouldn't trust pep boys to ever touch my car. I've heard some really shaddy things about them, and their work is crap. besides I do most of the work on my car myself, if someone is to blame I'd rather it be myself.