Hows it going guys? So i have a stock head unit in my 2006 Monte i had a some new pioneers speakers installed for the door and the rear i had a 400w 4 channel Sound Storm Evolution EV4.400 Amplifier installed also. quality is not great not so bad but it all i had its an amp from my old car,its definitely louder but im keeping at a very low setting almost the lowest because of distortion. i would like it louder and better quality what is my best bet to get to better quality and volume i can only do one at a time a new aftermarket head unit or an amp ? i didn't want to get up-selled by the install guy. thanks for your help guys

 

You should probably go for a better amp because the headunit doesn't really matter when you are adding an aftermarket amp for all four speakers.