Well, I finally did it, it took me the entire day to finish it, but I think it was worth it. I took some pictures as I went along.
Here's what I started with...
Here's what it looked like once I got the dash off. I planned on having the dash on the ground, outside of the car by noon. I had it out by 11:30
Here's the 2 side by side while I swapped the harnesses. I suggest doing it this way so that you can look at the 2 harnesses to see the difference in routing. This will make life a lot easier.
Once I had the dash out I took a couple pictures of the gap difference if you are thinking about putting 300m door panels in without putting in the 300m dash. This is sort of the opposite situation, but it will give you an idea. The gap is very noticeable, I know a few had asked about this, so here's the proof.
Passenger side from the outside...
Passenger side from the inside...
Now here's the comparison once the 300m panels are on. Muuuuuch better...
And here is the finished product. Finished before dark!
Some things I found out that I didn't know:
1. There are actually slightly different sizes in sail speakers between the Trep and the 300m, never knew this, good to know.
2. You don't really need to remove the front seat to get the dash out, it might make it easier, but it's not neeeded.
3. You CAN do this whole process alone, a second set of hands would make life easier, but it's not needed.
4. There is a difference in the door-pull-cups from the Trep and the 300m. The screw hole is in a different place, I need to find a new one on my next trip to the yard, I damaged one in the process of installation. Nothing I need to warn anyone about, not something you might do, just a stupid move on my part.
So, if anyone is planning this mod, just ask me any questions. I might not be an expert, but I have done it successfully, so I can help. The install is not really that bad, they really are plug&play. All the screws match up and the wiring is close enough to be a breeze. The only thing that I needed to rewire was the connector for the clock (I reused my old harness) it wasn't too hard, took me maybe 15 minutes to complete.
Let me know what you think.