Audio upgrades on my max- questions

[mattlikespeople]

Ok, so with my new car i've only got one major gripe. The stereo sucks balls. well, the speakers do and since i dont have decent equipment to test just how amazing the stock head unit it i'm going to assume it's either on par or only slightly better than the speakers.

Dont know if there are any car audio buffs here but these are the components I was thinking
Front component set:
Polk Audio db5251 5-1/4" component speaker system Certified for marine use at Crutchfield.com
rear doors:
Polk Audio db651 6-1/2" 2-way car speakers For 6-1/2" and 6-3/4" openings Certified for marine use at Crutchfield.com

I've currently got 2 JL audio 12w3's and a kenwood 1000w amp pushing them but i want to go to a single speaker due to trunk size and weight. This is what i'm thinking of replacing those with
Boston Acoustics G512-4 12" 4-ohm subwoofer at Crutchfield.com

Found much better prices for them than crutchfield but they offer the best presentation of the product.

In addition to the speakers i would like to get the dynamat (or similar product) door kits to really clean up the sound and maybe the trunk kit as well.

[HKSemo]

i havent heard polks in a car, but our bose home entertainment system has a polk audio subwoofer system and that thing shakes the neighborhood

i say keep one of the JL subs and the 1000 watt amp...just get a single box for it
JL in my experience is thee best subs

[mattlikespeople]

that could save me some money but i bet i could get 350-400 for them which would bring my speaker costs to around $200 total. but i'd still need a box for the sub and a head unit... tack on another ~300 bucks