I just installed my dc 4-1 header today on my GS. THe mods i have are AEM short ram, the header, type R cat, type R exhaust.

after installing it, i didnt realy feel any top end gains and felt like i lost some low end. I havnt dynoed it yet but i am quite disappointed with the results.

what could be wrong my friends? should i of went with the 4-2-1 instead?