If you're wanting to close up that wheelwell gap, without sacrificing ride quality, a product like the Eibach Pro-Kit Spring Set would be a great solution. You'll see a mild drop in the 1.0" - 1.5" range which will improve the stance and handling while maintaining a near factory ride.
Are you ready to hit the track while wanting a wide range of adjustments (including your Ford shocks) for your vehicle? It may be time to explore a coil-over kit. Again, Eibach steps up to the plate offering drops adjustable between 1.0" and 2.4". The Multi-Pro Coil-Over (shown above) features a 10-way independently adjustable compression and rebound which allows for combinations that are near limitless to dial your car in perfectly.
Options are available for most years and models of the fifth-generation Mustang (2005 and up).
Whether you're looking to buy shocks online or purchase a coil-over kit, shop by vehicle to find the right suspension products for your vehicle.