Ok just finished with my open cone install on my 04+ GTP . Spectre # 9732 $40 at auto zone ( uninstalled the stock box and hooked up the cone filter directly to the MAF adapter). Cut my stock box in half with a skillsaw(the box has a line guide where it was glued together) cleaned it ziptied it and installed the PCM , I also ziptied the cone to the body .
Before
After
Took about 1 hour to install, cut box and put together with zipties