Tony,
The steering in my 67 has the AGR steering gears and it works great. Everyone that's driven the car comments on it. I haven't driven a Camaro with anything other than stock so I can't tell you about other products, but I'm very happy with the feel the AGR kit provides.
http://www.agrperformance.com
Not sure about your header issue. You may want to contact AWR68. He's pretty good with that kind of info.
Good luck!