Yes.. you got it backwards. A 4-1 Header will not give you good low end or mid range.... all about upper Rpm's with a 4-1. A 4-2-1 header will give you better all around. And yes... i would choose a header over catback. Being that you have a GSR.... I would go with a Nice 4-1 Header.... Maybe even an OEM ITR 4-1 Header. You will not be dissapointed



-Joe