I just had a look inside the door speaker box and noticed this, is it a crossover? I assume yes, so I'll have to cut out/bypass if I'm using an aftermarket tweeter with it's own dedicated crossover . I assume the factory crossover would not be suitable for the aftermarket Audison tweet.

in case you find the photo confusing, thats a mirror I'l holding inside the speaker box

 

I did a little research and the factory crossover will not work with aftermarket speakers. I move the speaker wires on the terminals inside and now have no internal crossover. The key to the job was drilling a hole in the back of the box to get a Phillips screwdriver on the crossover mounting screw. I then desoldered the crossover and made a direct jump for the speaker wires on the existing terminals by resoldering directly onto the crossover terminal