k i have a very simple system in my 400. when i got it the PO had replaced the factory sub with a JL 8w3 which sounded ok. but honestly a freeair sub sounds much too sloppy for me.
i'd like to say im an audiophile in respect that i install stereo systems for a living going on 6 years now... but i cannot say that the equipment i am using in my car is worthy of my ear... however, my point to make is that with the right install u can make most anything sound decent for the average ear.
so heres whats im rollin with as of today..

molding the dash kit a bit.. i didnt want someone to just stick some keys in the side and jack my $400 stereo. also i hate the look of the cheap kits and trim rings and what not...
alpine cda-9855
front speakers are some eclipse 4" handme downs i got froma customer. i plan on doin some focal KF's in the front and modding the door panel to show em off. and for the record... focals are nice but not the best speaker out there.. although last week i put the $1200 pair in a honda and it sounded amazingly clear on opera and jazz after i eq'd it.. gettin off topic.
rear speakers... stock. i rarely run rear speaks.. never hear em anyway.
sub and amp i got for $150 from a friend and decided to upgrade that JL 8" which is now in my home theatre setup.

my trunk as of now.. when i get better equipment i'll flush the amp into the side panel.. thinkin i might do JL HD amps.. one on each side of the trunk.

and a side shot of the box... i made it as shallow as possible so had to stretch some fleece and use some glass. didnt wanna give up much trunk space but wanted to do something that looks nice.
thats all for now.