im looking at finishing of the system on my ba gt but i m not sure what size headers to go for im looking at eather 1 3/4 or 1 7/8 or i have seen that huracnie do a steped header 1 3/4 upto 1 7/8 would these the better way to go? thanks

I wouldn't use any larger than 1 3/4" unless the engine has some serious work done port wise and in rpm capability.
The stepped header is also questionable in a street engine but I'd like to hear from someone who has used them and what the engine combo is?
I've just fitted diflippo 1 3/4" and it certainly has maintained the low end and improved the midrange punch.

+1 for diflippo