Friend of mine is trying to install a Sony XAV-AX1000 into my 2004 MK3 MR2. This picture from MR2-Ben is identical to what I have bought. This says it is for non-amplified versions. Is there a different version of this for amplified version because I've got 2 spare connectors as seen in pic #2 which on the original unit were plugged into the two sockets indicated. As it is there is only a badly distorted sound coming out of the tweeters and nothing coming out of the main speakers. I'm sure there should be something going from the spare connectors into the back of the Sony.
You could try and check whether the pinout matches. This diagram was helpful to me when I was fixing my radio:
(https://pinoutguide.com/images/upload/pinout_1200434742_58812-pinout.jpg)