Let me just start by saying to anyone wanting to do this to their car... I wish I had never touched them. The coolness factor isn't really worth the amount of work.
A few years ago I decided to get JDM folding mirrors for my car. I had read the how to (NorthUrsalia.com: STi Version 6 Power Folding Mirrors). I found some on eBay, ordered them, got them, started to pull them apart and realized they weren't going to work. I had bought the wrong versions not realizing there were early v3/v4 versions and later v5/v6 versions are different! It took me a while to resell them and find a newer set.
When I did find the right set, the install was more or less like in the how-to link above. I spent a lot of time running a wire through my existing door grommet hoses for a clean install. I broke 1 mirror in the process. Kind of a pain but I figured it would be worth it in the end. Wrong... What I didn't realize at the time is how they fold in. Because you use the USDM triangular bases (which you must to be able to see anything behind you in a LHD car), the drivers side mirror will not fold in enough and the passenger mirror will fold in too much.This bugged the hell out of me, to the point where I thought about going back to USDM mirrors. I decided to just keep them that way until I had more time to look at them.
Finally I had some free time so I decided to mess with it. I figured worst case, I break something and lose the electric mirrors that I wasn't really happy with. I'm happy to announce that they fold in parallel now. I probably would never do this again, but I'm glad it's done. Here's a video of them working now:
After you remove the assembly from the mirror shell, you need to pull the black plastic cover off the motor assembly. It's glued on there really well and takes some time.
Then you remove the motor and pull the wires out. The motor comes out with the metal casing. It's held in with 2 screws. It will look like this after:
Carefully remove the gears. THey just pull out.
Now the hard part. You need to remove that metal clip that holes the spring in. I tried a bunch of things. Pliers, prying carefully with a screwdriver. I finally used my press very carefully. It works really well for the drivers side. It actually broke the plastic though on the passenger side Fortunately what it broke wasn't real important.
With my broken piece you can actually see really well how it works. The metal base has a tab on it. This tab rides in a slot on the mirror. It provides a stopping point for the mirror open all the way, and a stopping point for the mirror folded in all the way.
So on the drivers side you need to actually make the slot longer so that the mirror closes more. On the drivers side you need to make the slot shorter so that the mirror doesn't fold as long. Hopefully the pics are self explanatory. I used plastic 2 part epoxy that you can get at any hardware store for like $5-6. I used a Dremel with tiny tip to make the curved slot tracks longer.
There was just a thin wall of plastic stopping the drivers side. So in order to make the curved slot longer I had to completely remove the wall. THen I had to add epoxy behind it to make a new wall.
I found it was best to add more plastic epoxy than you need. Then Dremel some away, and check fit. With it all apart it's easy to hold it back up to the car to see how far it would curve in. Repeat until it's parallel with the car. Then re-assemble carefully. I used a press to reattach the collar lock that was a pain to remove.