hey there altea have already very good speakers but i changed them too

look the bEst you can do its that modified all your door panels it cost to me 20 euro per door.make holes for 6x9 speakers and bought something like that they are good and cheap emimikos.gr/
shop/product.php?productid=23216
now bridged back door speakers and send the cables to the amp 125w 4ch is very good and now if u want subwoofer do exactly what i do i have an Pioneer Sub 400 w and i bought ebay.com/itm/Car-PC-300W-Hi-Fi-MP3-MP4-Speaker-Amplifier-Stereo-AMP-/220377172785?pt=US_Home_Audio_Amplifiers_Preamps&hash=item334f80cb31 thisone i bridged front door speakers and i connect it to this amp at bass output. if u want you can connect 2 more 6x9 in 300 w output but be carefull it must be 400w

. my car is amazing right now evryone like to come with me they love my clean and toooo loud sound