I know this is an older video but I dealt with the same issue and tried everything from cutting stock bolts to 3 different types of aftermarket lowering bolts. They all sucked and tore apart. Then I went with coilovers! Done deal! Plenty of adjustment and looks perfect.
You should measure from the center of the wheel to the fender not the ground to the fender you'll get a better measurement.Sweet looking car looking to get one soon.
Nice little upgrade to the C6 lowering style.. my next vehicle when I retire is going to be a C6 Z06.. the color I want is competition silver and of course boooooone stock..