Audio Systems: 93 Toyota OEM, watts rms, stock speakers

Question
Hi Cody>  I shall outline as clearly as space allows my present endeavour. Upon searching the web regarding car audio upgrades, my thoughts of what really made for better performance at minimal expense seemed substantiated. My plan is to keep the factory fm/cass head, which sounds quite satisfactory thru the door and rear speakers. Using the cassette adapted Walkman for CDs works for me, and remedies theft concerns.
As of today, I have accessed and removed the head unit and obtained both male and female harness connectors. Also ready to go are a 7 band 20-20k EQ with hi and lo inputs and 4 output circuits. The 1/2 DIN sixe fits well in the dash and powers up on initial test. A 10" JBL sub with box and 2 channel bridgeable amp with lo input only awaits connection. This brings up my questions for you: Is my scheme to use the four existing speaks thru the EQ and sub thru the new brided amp reasonable? If I have a cable raw at one end and matching the 13 pin 1/2" round DIN connector at the other, can this be utilized for a lo RCA output to feed the sub/amp? Is using the line level output to the EQ a problem? I have compiled all appropriate wire color and pin function data, and wire work shall happen only between the harness extending connectors and Din cable, I hope. I need some confidence to press on, and am open for real critical thoughts. Thanks awfully for your time. >Will  

Answer
Will,

  i dont normally recommend using an exsiting stock unit for the foundation of a higher end sound systems .. but it can be done and give fairly decent sound and function not as high and as compatable/expanadable as aftermarket .. now from what i gained from your description you want to power the 4 stock speakers through the EQ which is fine depending on the EQs wattage mainly RMS .. the stock factory speakers will hold up to about 25-30 watts RMS for awhile but will eventually blow rather easy from the extended use this is where if the EQ produces atleast 20-25 watts RMS i would advise upgrading the speakers you plan on powering .. now the part i dont understand is the "RAW" DIN connector but your amp will need the LO output RCA cables which you said the EQ provides this is the best performing output/input method the high input/output which requires the mending of (-)&(+) wires from all 4 speakers isnt as clear and crisp as the RCA .. it sounds like you have a good plan laid out and you should have the confidence to push on just take all the simple precautions when doing the wiring and install and also for your sub/amp selection RMS watts are the most important to match up with your sub to ensure nothing is overpowered and can cause damage and also inline fuses .. i have a resource page with some subwoofer wiring diagrams and some other helpful stuff you can check out if you need anything
http:www.geocities.com/evilparadise02/stereo.html

if you need anything else let me know

thanks