[phutyle]

Plenty of threads about installing the auto dim mirror. Just make sure to get the right one a) for the year of you car (pre or post 2008), and b) whether you have a rain sensor or not (2 different wiring harnesses). If you're doing it, you might as well get the one with the digital compass. They're very expensive new, but very reasonable secondhand.

Which leads on to installing the rain sensor. I really doubt it's possible. You won't have the wiring, the button on the stalk and probably won't have the cutout for it in the black part of the windscreen. So even if you managed to get the wiring (which in itself is unlikely), the new stalk (unlikely you have the wiring for the button) and a new windscreen, you won't have the software. I doubt it's even possible to get the software from a main dealer, but even if it was, it would cost hundreds.

So even if it was technically possible (which is unlikely), and even with second hand parts (can you get a second hand windscreen? Will insurance pay for a rain sensor one when your car doesn't have it?) it would cost a lot. Which is probably too much to pay for the small convenience of not turning on your wipers yourself.

That said, it it a feature I use daily. And when I got my car, it didn't work, as the previous owner replaced the windscreen, and they forgot to fit the clear silicone pad over the sensor. I fitted that bit myself, and it's worked great ever since. But aside from that, I wouldn't have gone to any great effort to get it if the car didn't have it installed already.