You can make it work, but you have to modify it. The splines are different.
I ran a 911 wheel in my 914 for a while. I made it work by removing the 911 wheel from its hub, and then installing the wheel onto a Momo adapter. The Momo adapter fit right under the factory housing, so from the outside, the modified wheel looked completely stock.
But I don't run it anymore. While the 911 wheels are nice in a 911, I found it to be a bit too big for the interior of a 914. So I went with a Prototipo, which I love.