pipe size from collector to tail pipe.

I was looking at the summit one just the other day. Not sure exactly what aluminum steel is?
I am going to ask some of the local hot rodders around the area where they got their pipes bent. I think that will be the best idea for now maybe.
I don't imagine it will be long here before some of them are out and about.
I am thinking 3" all the way out but no cross over for now.
Maybe I can take it apart next winter and add it in myself.
That way it will be done right and over with rather than hoping what comes in the box fits correctly.
Thanks again all.
It's getting close after 3 years, can hardly wait. :burnout::cheers: