So in my 87 I have the original head unit. No Aux unfortunately. Come to think of it, I don't even know if Aux existed in car stereos in 1987 .
Anyway. That unit, this amp under the seat
Fosgate 10" R1 Subs in ported box with divider,
Fosgate 6.5 R1 door speakers. Bluetooth FM adapter.
Unplugged both antennas to cut down on FM interference in L.A. area
Honestly it sounds really good for what it is.
Anyway. That unit, this amp under the seat

Amazon.com: Alpine MRV-F300 4-Channel Car Amplifier, 50 Watts RMS x 4 : Electronics
Buy Alpine MRV-F300 4-Channel Car Amplifier, 50 Watts RMS x 4: Multichannel Amplifiers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
Fosgate 10" R1 Subs in ported box with divider,

Amazon.com: Rockford Fosgate P1S4-10 Punch P1 SVC 4 Ohm 10-Inch 250 Watts RMS 500 Watts Peak Subwoofer : Electronics
Buy Rockford Fosgate P1S4-10 Punch P1 SVC 4 Ohm 10-Inch 250 Watts RMS 500 Watts Peak Subwoofer: Component Subwoofers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
Fosgate 6.5 R1 door speakers. Bluetooth FM adapter.

Amazon.com: Rockford Fosgate P165-SE Punch 6.5" 2-Way Component Speaker System with External Crossover (Pair) : Electronics
Amazon.com: Rockford Fosgate P165-SE Punch 6.5" 2-Way Component Speaker System with External Crossover (Pair) : Electronics
www.amazon.com
Unplugged both antennas to cut down on FM interference in L.A. area
Honestly it sounds really good for what it is.