smp_123

Hi,
I am trying to replace the front door mid-woofers from the 9 speaker (Dash Tweeter: Left / Center / Right - Front Doors: Left & Right Mid-Woofers - Rear Panels: Left & Right Tweeters - Left & Right Mid-Woofer) set up in my vehicle. The head unit is a MMI unit. The issues are as follows: The driver in question are: 8J0 035 412A (2ohm) which are a complete pod some 8.5 inches in diameter. I am looking for viable simple options to replace these, either by modifying the pod to accept a 6.5 driver or something more elaborate...
Further to this is the issue of the impedance of the driver, 2ohm this is a little concerning? I am also somewhat confused as to how the speakers are configured, does the amplifier have 9 channels separately equalized to match the frequency response of the driver? does it have five channels with independent crossovers for each corner (if so where are they)? With my simplistic understanding I feel based on the impedance of the Mid-woofer, the following may be true; the amp is 5 channels, each corner is wired with the Mid-woofer and tweeter (all 2ohm) wired in series but the tweeter has a high pass filter of some description wired in series (it seems as if an electronic component of some description is wired in series between the positive input and the driver) This is borne out by the fact that if a full range driver is connected directly to the tweeter wires the audio seems full range but if connected after the electronic component out then only a high frequency response if obtained? My fundamental question is if I replace the front left and right corners then which wires should i use for the input side of the crossover? I am sure if i tore the vehicle down i might be able to work this out? But i hope the knowledge, experience and wealth of understanding contained in the members of this forum I might be able to glean this information from someone who has already trodden this path.
Furthermore the entire make of this system is unknown to me, does the head unit send "Line Level" or "Speaker level" output to the amplifier (no RCA or similar are present at the amplifier, but there are numerous twisted pair conductors) The amplifier that is located the rear driver quarter panel gives little or no help, does anybody know how this wiring is configured for future reference, amplifier model number is: 8J0 035 223 F
Thanks for reading this , I hope you can help

smp_123

Update ;My hypothesis of the corners being wired in series is incorrect, the removal of any one driver does not stop others from working, not possible if wired in series, the plot thickens?