No, that bolt moves in unison with the tire, and will not change it's spacing.
I would recommend the Pedders springs, we offer some of the closest tolerance springs on the market, and a full line of suspension parts for the 300.
One of the things you may also want to think about with the lowering of the car is the bump steer, (toe change with ride height variation) and this can tend to kill tires quickly with the stock parts, we offer a bump steer kit that is just over $80 and corrects this problem that is more noticable on lowered 300s
The Pedders Touring Kit comes with 4 Lowering Springs, 4 High Performance GSR Shocks that provide a great ride, and the Bump Steer Correction Kit, all in one package for you.
Wretched Motorsports