I'll be taking my car to Hi Fi Buys soon to see what they can do for a budget of approx. $1000.
They did a killer job on my Supra with an Alpine head unit, Boston Acoustics speakers, JL Audio subs (two 10's in one enclosure), and two JL Audio amps (500 watts each, separately powering the speakers and subs).
Don't want to spend that much on the Mustang.
'11 BMW 328i (wife's car)
'02 Corvette Z06
'02 Corvette Convertible