From something just a little better than stock, all the way up to SQ and SPL competition vehicles, SVM Audio can design and build it all. I specialize in integrating aftermarket audio into existing Ford setups on the S550 Mustangs, using a custom breakout box, we simply remove your factory amplifier and plug your factory harnesses into my custom designed breakout box, with no factory wiring needing to be cut for integration. This allows for the addition of two amplifiers to your factory setup, all while maintaining control through the stock SYNC system, and retaining functionality of your steering wheel controls. Increase the sound and quality over stock and add some bass to the back, the options are limitless. I proudly use Skar Audio components as my recommendation based on performance versus value. Check the high end brand stats and price and then compare them to Skar and I think you'll see why. I can of course use whatever brand you prefer, the decision is all yours. However, if you're undecided, give Skar a look, you won't be dissapointed. I am in no way affiliated with them, just a huge fan of their product.