JL Audio 12 W6 or 12 W7 for 2009 Chevy Malibu?

Both of those subs are pretty high powerful and if only adding a sub and not doing speakers or any other components i would look at something less powerful. If you are between those two though go with the w6 as its less expensive and will be more than enough bass for your malibu. The sub can only output as much as the amp gives it though so finding a good amp is very important. Generally You want to match the sub and amp based on their rms rating and resistance(ohms). So if your sub is 600w rms like the w6 is you want an amp that puts out about 600w rms. Any less you wouldnt be using the subs full potential any more is not needed and will just cost you extra money you dont need to spend. Also make sure you look at the resistance rating (ohms) make sure the amp is rated for about the same rms at the same ohms that the sub is. The w6 can either be run at 8 or ohms because it is a dual voice coil sub and each voice coil is 4ohms. so you need to find an amp that would do 600w rms at 2 ohms or 600rms at 8 ohms. Finding one that does it at 2ohms is cheaper as the lower the resistance the easier it is for power to flow