I've probably just confused myself from all the searching but can someone PLEASE clarify the 2 packages? First of all, does a 2013 Mustang GT Premium (Manual) come with 3.73 gears? The Brembo brake package comes with: Front: 14" Brembo® vented rotors with Brembo® 4-piston calipers Rear: 11.8" vented rotors Unique electronic stability Control® (ESC) tuning 19" X 9.0 dark stainless painted aluminum wheels with 255/40R19 summer-only tires Tire mobility kit replaces spare tire Aggressive suspension tuning--is this the 55D Rear Springs? Track Package: Available only on manual GT Mustangs with a 3.73 axle, the package gives track enthusiasts an engine cooler, upgraded radiator, performance friction brake pads and the same Torsen® differential that's on Mustang Boss 302. The package includes everything in the current Brembo™ Brake Package, with 14-inch vented front discs, unique 19-inch alloy wheels and summer performance tires. My question is--do you get different springs with the Brembo PKG and the Track PKG? Is the Track PKG the only option that comes with 3.73 gears?