Header, Intake, & Exhaust - Hi Flow Cat

Getting ready to put new header and cat back on my 05 LX, do i need to install a hi flow cat also, to see any increased power or can the cat stay stock? Also we have strict emissions inspections, will a hi flow cat pass these inspections? If so any one recommend a good one?

u dont NEED one...but itd b a good idea, u will see some power gains...though slight

as for inspections...they should pass, but im no expert

get a magnaflow, its around 60 bucks