I just bought an 04 Spec V and want to buy a header for it ASAP! I dont have enough money for a new exhaust right now so to my knowledge a 4-1 header is the only thing that will fit to my stock exhuast. My question is will I have less low end torque with an aftermarket 4-1 header than a stock header? Or will it be about the same? Also, if I was to get a 4-2-1 header with a high flow cat welded on, would that fit my stock exhaust? I prefer 4-2-1 for more low end torque but not sure if it will work. Thanks and Happy Thanksgiving everyone!