[yeloZX3]

as more and more mods are adding to your mod list, a race header (long tube) will give u more and more gains above the shorty header

for a car with only intake and exhaust, yes the long header will just have about 2-3 horsepowers over the shorty.

but when more are added up like cams/cam gears/pulley/chip/intake manifold ....... the differences between long tube and shorty will be very noticable.

note that, a shorty with high flow cat is very loud and sounded bad (ppl call that sound rice)

i am running race header, bosal flex, universial cat (non hi-flow), borla exhaust (no resonator) and this sytem is not that loud (i also have ported 2000 IM and stgII cams that's tuned), some ppl in this forum have heard my exhaust before and they said is not loud.
although i'm having a non hi-flow cat, my car still have 146hp and 141tq at wheels, and with a hi-flow, the car should be able to push to 150hp or close to 150.
with a shorty and hi-flow, it should be about 140hps with my mod list coz the flow just isn't enough although it has hi-flow cat already.

about emission, my car passed twice with race header and the cat welded right after the flex pipe.