My 1st Suggestion Is To NOT Put 4X6 Speakers In The Front Doors! The Reason Is, You Would Have To Modify The 4X6 Plastic Speaker Holders For Anything Other Than a Factory Speaker. I Have Done a Couple and Needed To Use a Dremel To Mod The Holder Because Of The Larger Magnets On AfterMarket Speakers. Save Yourself The Hassle And Make Hacks 6 1/2 Wood Speaker Brackets As Shown In This Link. (Click On The Pics For actual Sizes).
Impala/Caprice 6 1/2" Speaker Templates
This Setup Works Much Easier And Sound Better!
You May Want To Consider This Alpine Amp If Your Looking For a "5-Channel Setup". I Have This Amp In My Caprice (Alpine MRV-F450). The Specs Are As Follows:
50 watts RMS x 4 + 200 watts RMS x 1 at 4 ohms
60 watts RMS x 4 at 2 ohms + 200 watts RMS x 1 at 4 ohms.
120 watts RMS x 2 + 200 watts RMS x 1 in bridged mode.
2-, 3-, 4-, or 5-channel output
requires 8-gauge power and ground leads ? wiring and hardware not included with amplifier.
Bass Engine features:
front and rear channels have variable 50-200 Hz high-pass/low-pass crossovers, 12 dB/octave
sub channel has a 30-200 Hz low-pass crossover, 12 dB/octave selectable (15 Hz or 30 Hz) subsonic filter on the sub channel tuned Bass EQ (6 dB bass boost at 50 Hz with adjustable Q factor, while frequencies below 30 Hz are cut by 6 dB) on the sub channel.
MOSFET power supply.
STAR Topology (minimizes internal noise and prevents ground interference)
oversized power and ground connections
gold-plated screw terminals top-mounted controls with cover detachable front cover, blue power LED
16-9/16"W x 2-1/2"H x 11-1/4"D (depth is 10" with front cover removed).
Here's The Link To This Amp, It's Alot Cheaper Off E-Bay Than Crutchfield Or E-Tronics....Mike
Alpine MRV-F450 Amp