just got bbk header but i have a question...
 

i have a 97 gt... but i have a 2002 motor and 5 speed trans... i have an accufab 70 throttle and a ported stock plenum with a k&n filter... then i cut off two cats on my h-pipe and i have a borla rx-1 cat back... and im running 4.10 rears...

my question is what power gain will i see with bbk tuned shorty headers by them self... and how much gain with the bbk's and a x-pipe with hi flow cats.... can you please let me know... and how will it sound???

You will get a slight increase in HP. I would guess 10 - 15 HP. You might notice a sound difference. Notable sound changes come from muffler and mid-pipes changes.

You might have considered long tube headers which when used in combination with a shorter x-pipe can net 25-35 RWHP.