For the MA70. The sub in the boot install wasn't too bad, on the firewall you should be able to find a rubber plug, take this off to reveal a hole you can pull thru your heavy guage cabling. I ended up bring mine thru ther drivers side, routing it under the carpet to the back, and to the amp, the negative lead earths straight to the car's body in the boot (under thge carpet bolted to the metal)
Make sure u put a fuse near the battery for the Positive lead.
It's not to hard to remove the doors to get to the speakers. Start by removing the screws that hold the doorhandle and take that off with the window controls (they unplug) then take off all the screws along the bottom of the door, the door handle has 1 screw (the bit you pull up to open the door) And finally there are 2 gold colored screws under 2 plastic caps towards the dash side of the car. Now where the red light is lift the trim away from the door and unplug the red light connector and you should now be free to completely remove the trim. You may have to remove the speaker grill i cannot remember.