What do you get for $18,500? First, bare carbon fiber 20-inch wheels wrapped with Michelin Pilot Sport Cup 2 tires that are a half-inch wider in the rear (11.5 inches). On top of that, you get a GT4 track wing with an integrated dive plane, front splitter wickers, and a rear seat delete. All that for about 70 percent the cost of a base Mustang EcoBoost.
For a whole lot less, the Handling package puts a Gurney flap on the standard rear spoiler and adds the aforementioned splitter wickers. It's only $1,500, but you can't choose it and the Carbon package together. The Recaros that are included in the Carbon package are a standalone option with an MSRP of $1,595, however.
The last big ticket item is the Technology package for $3,000. This gets you a B&O sound system, a 6-way power driver seat, heated mirrors, Sync 3 with navigation, BLIS and cross-traffic alert.
That said, the GT500 is more expensive than the Chevy Camaro ZL1, Dodge Challenger Hellcat Redeye, and even the ZL1 1LE. The ZL1 starts at $64,695, and the Redeye at $73,440. Of course, the ceiling on the GT500 is far higher than both, as well. It's also over $12,000 more expensive than a Shelby GT350, which produces 526 horsepower itself. You can get up to speed on everything the GT500 offers over its less powerful sibling here.