My friend has a TW VR-X sedan. The centre brake light assembly at the top of the rear window has fallen off. What's the best stuff to use to put it back on so it doesn't fall off again?

I used 3m double sided tape, (exterior stuff). Nothing else worked for me.

I used loctite 406, but at 20 for a small bottle, its hard to justify.
Its also hard to remove if you stuff it, as with superglue.
You could use sikaflex, but what ever you use.
It must cure to full strength before reattaching, or you'll end up doing it again.
Best letting it sit for a day or two before refitting.
It also must sit flat, or.you might end up with light leakage, noticable at night.

I had the same problem, i used arildite? you mix the two chemicals together and it's strong as f*ck to hold it :)
even in this 40 degree weather now!