Appreciate the input on the header and exhaust question... I've spent quite a bit of my spare time reading on the subject the past few days. We've pretty well resolved to route it to the back but as to the specifics, well, that's a problem for future me.
Just as a quick update on the car - ordered a lightweight steering column from Midwest Chassis for installation into the Trans Am. It arrived last Friday, was installed Sunday. Works well with our manual steering rack conversion. We opted for the SFI spec steering wheel hub. Didn't see anything in the rules requiring it but better safe than sorry... heck, it was only a few bucks difference in the end so why not?
We should finally be going in Saturday to drop the car off at the shop to begin rollcage installation. We're about a month off of our original date now but it's not a big deal... we had hoped to be able to thrash and bring a running car to WoS this year and at least get tech'd and make a few runs but life happens so we'll still plan to attend WoS, only as spectators and not racers.