The easiest way..
Pull out the Factory Headunit
Pull out the Factory Speakers
Toss the Factory Amp, in the Trash
Replace Head Unit ( Double Din ) FTW !! 20 mins
Rewire Car 2 hours
Replace Stock Speakers With New Components FTW!! 1 hour
Wire Amp and 12 Volt Wire And a couple sets of RCA'* 30 Mins
Add a 5.1 Amp to power Speakers 45 Mins
Add a small 12 inch Sub and Enclosure 20 mins
Tune Amp PITA but worth it !!
Jump in and go for a ride !!
I dont wanna hear it takes less time LOL.... I tape all my wires Run power down one side and RCA'* down the other !!