airpipe is connected to the main cat. I disconnected it form the cat and installed the midpipe. (I don't have an airpump)
can I just leave the airpipe open like that or do I have to block it off?

 

if you have a block off plate, block it off.... but you need to block off the other things that have to do with smog i belive... im not sure on this but i posted just because i put a blockoff plate on mine today...

 

can I just leave it hanging there and drive the car before I receive a blockoff plate? If I order the plate it'll probably take a week.

 

yea, its no prob! ive left it open for a month... its suppose to blow out air but if your pump is not on, dirt and rocks can get in there.. but its high so i wouldnt worry about it!