I install mb quart component speker for front than the shop ask me to install another com speaker same brand but dif model at the back speaker is it necessary to have both front and back comp speaker it cost me rm1800 for 2 pair of speaker. Is it ok or not necessary if not maybe i instal the other comp speaker in my wife car.

after i change speaker still dint satisfied with the sound and i changed the hu to 2 din pioneer and it came with free 2 chan amp. Should i changed it to 4 channel to get better sq. I drive grand livina.

Thank you in advanced.