Ordered the brakes today. The 12" sport will fit with the American Racing GNX look alive rims. I ordered 1/4" spacers anyway just to be safe. The clearance limiting factors are the location of thecaliper with respest to the inside face of the rim. The 12" street set has a caliper offset from the hub of 0.08 inches whic the sport is 0.35 inches. It looks close but seems to have well in excess of the Baer recommended clearances. I also ordered a 13" track set as well for my buddy. I will try them both to see if the 13" clear but it appears to rub from the templates on their website.
Nothing like ordering $3K worth of brake parts!!!!!
BTW, thanks to Rick Elam he was super helpful and overall a class Buick guy. Thanks Rick.