maybe im blind but i cant seem to find the diy for the mounting plate for 6 1/2" door speakers With the base model 04 rx8 anyone know where I could find this?

 

Here's some ready made.

Don't think anyone has made a DIY. There's nothing to really write about. Buy a sheet of ABS plastic or Lexan, hold it up to the existing screw holes and screw it in. Mark off the excess, then unscrew and cut off the excess. Use the mounting template that comes with most speakers and mark out a hole for your new 6.5" speaker (or use measure tape/hold the speaker against the abs and mark it). Cut it out and you're done.

 

I used the adapters listed above. Delivery was quick, install was super easy and the price was good. I'm pretty happy with these adapters no rattles and the predrilled holes were very helpful. I went back and forth about just making them, but in the end I choose the easy route lol. Also if I remember correctly if you send a pic of your install they refund half the cost back.

Keep in mind if you are planning on running the components from the Bose amp it will not work well. The Bose amp is only .5 ohm impedence to the doors.