What do I upgrade First?

[Camo3545]

Hey everyone! So my sister just got a car and she gave me the task of upgrading the audio. The car is an 2007 Cobalt. My Question is what to upgrade or add first? Like door speaker or sub woofer. Any if you could give some recommendations to what i should get. Her budget is 400-500$ for right now.

Also any tips or trick for installation would be great!

[Terra Rysing]

I would start off with a new head unit and then door speakers.

[Phaeton]

if your door speakers work, add a sub. if the door speakers are horrid and cant stand them, do them first.

[Terra Rysing]

The gm head units and speakers are trash in the cobalts.

[BigManAC]

Start off with a good HU that has useful interface like Bluetooth. If the door speakers sound good and you are not getting any static from them go with a single 8" or 10" sub. That will round out the music in the car without getting crazy or over budget. Yes I know ones like DC's get crazy loud but a simple 8 or whatever will do the trick. SoundQubed just came out with their new 8" and I know sundown makes great 8 and 10" subs as well. Those are the only two that come to mind while staying within the allotted budget.