I知 wanting to put a system into a 2003 Monte Carlo I just bought but don稚 know much about the specs yet as I don稚 wanna take stuff apart until I知 ready to install( busy schedule with work little time to do much) I got a 12 inch sub for the back along with an amp to run it a set of kenwood speakers that iv had for awhile but never got to use my question is what sizes do I need for the front and rear speakers? Would I be better off to put a sub box in the trunk or build it to fit between the two rear speakers? Any advice would be greatly appreciated I知 new to monte Carlos but iv already fell in love with the car (sorry babe) I知 wanting a nice system which I知 going to work on over time and I知 a bit of a beginner to audio systems in a car so all advice is appreciated

 

Been out of audio for a long time, but IIRC speakers were 6.5" up front and 6x9" in the back.

As for the subs, definitely dont rear deck mount them. Cheapest and easiest setup is a regular trunk box. Few problems with a rear deck mount:
-You should really run subs designed to be in 'free air' as they'll have adjusted parameters to perform best in the ultra low resistance environment. Regular subs designed around a traditional box dont typically work well.
-Although the rear deck is metal, it's really fairly flimsy (at least compared to a legitimate sub box). You'll generally get some awful resonant frequencies from the deck moving.

2 10"s in the rear deck was actually my 2nd sub system in my monte. TBH it was also the worst sounding.