My left foot enthusiastically stabs the clutch as my hand eagerly grabs for the Ford Mustang GT Performance Package Level 2’s six-speed shifter. I engage first gear, and there’s that familiar “thunk.” Ever since the S550-generation ‘Stang was introduced in 2015, I’ve treated that noise as a secret code signifying, “Come hither and make mischief with me.”

But now there’s even more mischief to be made with the Performance Pack Level 2. For $6,500 on top of a standard Mustang GT, you get chassis and aerodynamic improvements that are above and beyond what you get with the Performance Pack Level 1. For starters, magnetorheological dampers come standard. On the Performance Pack 1, which costs $3,995, you still have to pay $1,695 to get MagneRide, so in reality, the PP2 is only $810 dearer than the PP1. Those extra Benjamins get you quicker steering, a mean-looking set of “Dark Tarnish” 10-spoke, 19-inch wheels, Michelin Pilot Sport Cup 2 tires that are 1.5 inches wider all around, and a ride height lowered by more than half an inch.

And that’s not all. Up front, the Performance Pack 2 boasts a stabilizer bar that’s 12 percent stiffer, while in back it’s 67 percent stiffer. Ford then beefs up spring stiffness by 20 percent at the front, and 13 percent in the rear. Rounding out all the improvements is a new front splitter that creates 24 pounds of downforce at 80 mph, and that’s balanced at the rear with a package-specific rear spoiler.

With all those improvements, the temptation...