my itr is stock except for an aem cai. i just bought a ceramic dc jdm spec 4-1 header + apexi n1 cat back. I know i need a 2.5 collector but how much better will it perform with a high flow/bigger cat or should i even bother?

Keep in mind that i am installing a JRSC in aswell. I'll only be running 6 - 8 lbs/ 8 lbs with hondata of course.

and 1 more big question for any forcefed pro's. This big boost JRSC as you most likely already know has an 11 lb boost pulley. Please tell me what I... (1) must upgrade so my baby don't detonate or wear and...(2) what is not manditory but is piece of mind to have when running 11 lbs with JRSC.
THANX A LOT FOR ANY INPUT/ADVICE!!!