I do not think that will be an issue, I've done it before without any problems. The only thing is that you'll need to file down the tab that the H11 has to make it fit, but other than that you should be fine. The other thing is that the Philips Crystal Vision, although it has a cool & great output, it doesn't last. I have been using it on my 4 year old Honda's headlight and I just recently replaced them for the 4th time. Luckily on the Honda, the headlight bulbs are easy to replace, for the Focus' fog lights, not so much. Best of luck with what ever you end up doing and please share photos after. Cheers!