DSC, I belive it's a little different for the S13.

Are you talking about removing the y-pipe?  you don't want to remove the resonator box, without putting on an aftermarket cone filter.  Otherwise say goodbye engine life.

To remove Y-pipe I removed the Resonator b/c it made it a little easier.  

Loosen screws holding the MAF onto the Resonator box, and wiggled the end out.  There are two screws that hold the box down, and two on the bottom towards the maf that have rubber mounting peices on them.  There is one screw that hold the Y-pipe to the resonator box, and one screw that hold the y-pipe to the body, behind the headlight.  Go ahead and remove those before starting.  Once you've removed the other two screw that hold the resonator, just put your hands on it and push it towards the Fan shroud.  The rubber peices should just pop out of the mounts.  Everything else is cake.  You may ne able to remove the Y-pipe w/o removing the Resonator, just wiggle stuff around.  It's really not hard.  I just took that stuff out b/c I was also cleaning the Throttle body, and MAF at the time.