I've got to figure out what backspacing to get on my wheels before i order them. I'm getting 17" wheels, and will be running Baer's Track System on the front with 13" rotors & Speedtech Tubular A Arms top & bottom. And the Sport System with 12" rotors on the rear. I gotta get the #'s right, cause the wheels take 4-6 weks to make. I wanted them here before i get all the suspension and stuff on. Thanks.

Bad idea.
Measure with all the items on the car. Then measure again with them still on the car. Then grab a different tape measure and do it all over again. Don't be lazy either, measure all 4 corners, as I've seen cars that varied greatly between the L/R sides.
Tyler

We put Baer brakes on my wife's 73 Camaro, I had to machine out the center hole in the Vintage Wheels we used because the aluminum ft hubs stick into the wheel farther than stock.
The Baer setup will move the wheel out, how far I don't know, as Tyler says, better measure it yourself.