For the Dodge Challenger or Charger, can the Modern Spare kit be stored in the existing storage well under the trunk floor?

Yes. With a few exceptions related to sound system options, the Modern Spare spare tire kit can be stored and secured in the space under the trunk floor.

Thankfully, the Dodge Charger and Challenger models have retained the storage "well" even after Dodge stopped providing a factory-supplied spare tire many years ago. Modern Spare has designed a durable hardware assembly to secure the spare in this space. 

This hardware is included with only one of the kit options for these models. Be sure to order the "Complete Kit Without Carrying Case" to ensure the securing hardware is included in your order. The securing hardware is not included in the Wheel and Tire Only option or the option with the carrying case. 

The Charger and Challenger models that will not allow for storage under the trunk floor are those with the optional Harman Kardon factory-installed subwoofer as part of an upgraded sound system.  For these models, the kit with a carrying case may be the best option for storing the spare in the main trunk compartment.