I'm installing an autometer boost gauge on my 02 24-valve, I ordered the adapter/reducer from piers performance but I'm having a little trouble figuring out where it goes exactly. Any help would be great guys. Thanks!

 

You take out one of the intake plate bolts, and install the Piers fitting in it's place.
Choose whichever one is easiest to get at.

 

Here's a link to the TST instructions:
http://www.tstproducts.com/gauge_install.html#boost