This looks like its only the kicker 4ch amp and the subwoofer. I would go onto Shelby take offs website as they all 4 speakers, amp, and sub for roughly the same price. There were also 8' door sub replacements but I'm not 100% they were included in that package.
As for SQ, I can think they will be better than stock but I have no experience with them. The huge plus is that it all interconnects with your stock unit. If u aren't a huge audiophile I would say this would be a great addition. And it really is plug and play. The equipment all has clips that plug into existing factory units. And they are sized to mount all concealed.
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2011 Kona Blue MT82 V6 Mustang Pony Package 3:31 Gear Ratio, Interior Upgrade Pkg, Security & Shaker500/Sync
Mods (in order of installed): AM Bama SCT SF3 Tuner w/ 87 Hybrid Tune, Airaid CAI, Hurst Billet Plus 2 Short Throw Shifter, Lethal O/R H Pipe w/ Stock Exhaust, Blacked-Out Tints on Rear Windows, Full Ceramic Tint on Front Windows, Metra Touchscreen Dash Adaptor, Single DIN Head Unit, 6.5'' Component Speakers Fronts, Stock Rear Speakers, 10'' Sealed Subwoofer, 4ch. and 1ch Amplifier. LED licence plate lights, LED interior dome lights, FRPP/Dynamic shocks and struts, SR Performance lowering springs, GT500 Strut Mounts, BMR Adjustable Panhard Bar, BMR LCA's, BMR Relocation Brackets. Rear Seat Delete.