Advice and opinion on new system setup

Also, I would HIGHLY recommend reading the rec.audio.car FAQ. Just do a
Google search for it. Reading through this will give you a pretty good
basic education on car audio.

MOSFET

If it all possible, I would try and use a separate amp for the sub and a
separtate amp for the mids. This will give you the ability to balance the
level of the sub with the rest of the system. It will also give you the
ability to control the sub volume from the driver's seat (either through the
head-unit or through a home-made poteniometer control which I have made from
$3.00 parts at Radio Shack). Being able to control the sub volume from song
to song is something you WILL DEFINATELY WANT TO BE ABLE TO DO, TRUST ME!!!!
Bass varies tremendously from song to song and besides the volume control,
the subwoofer control is the most used adjustment of my system.

I would STRONGLY advise you to do this from the start as if you skimp now,
you will only be frustrated and will ultimately upgrade later.

Howver, if you do go the one amp solution (have a two channel amp driving a
sub and two sets of speakers), you will need passive X-overs: capacitors for
the high-pass and inductors (coils) for the low-pass. You can also use
L-pads (passive componets) to balance the speaker levels. This, however, is
tricky for a person new to this and I would recommend having a pro help you.
But, again, this can be avoided by going with a separtate dedicated sub amp
as most amps today have BUILT-IN crossovers and of course L-pads aren't
necessary as you can use the gains to attenuate volume.

MOSFET

Beautiful, that was the answer I was looking for. Thank you.

Another question, If I get the dual voice coil sub, is that enough to
match the speakers or would it sound better with two subs running
parallel ( I think that will give a 2 ohm load or 8 ohm series or vice
versa, cant remember)?

I mostly listen to heavy metal, so midrange crunch is most important,
but having bass that makes your chest shake, now thats just plain
wicked!

2 x 500+ watts now their's some real power. Electrical meltdown.

...

First off, the only time your batery comes into play is when you listen to
your system with the engine off. When the egine is running it is the
alternator that supllies all the juice (actually, your battery is just
another electrical load when the engine is running). So I think your
question is really "will my alternator be able to supply the necessary
amperage for two amplifiers?", and the answer is most likely yes, no
problem. I run 4 amplifiers in my system (two of which produce 500+ watts
RMS) using the stock alternator in my Suburu Forester and though I can
certainly strain my electrical system, it usually has no problem keeping up.

I would DEFINITELY choose the two amplifier setup. A stock deck just can't
provide the necessary power for clean, dynamic hi-fi sound from any speaker.
But if you were to go with the one amplifier setup, I would amp the FRONT
speakers (and use the deck for the rears). A properly designed system
should have most of the sound coming from in front of you, like at a real
concert (when was the last time you went to a concert and stood with your
back to the stage?). Therefore you will want the front speakers to be
louder. Hope this helps.

MOSFET