According to the instructions on the site, you only need to "thread" the needles through the center holes of the panel so as to not mess with calibration. No need to remove them from the guage.
I'm still thinking on this one... I like it all especially the ability to make the colors to the ones I want but, am NOT thrilled with their choice of type faces. The only one that even looks good to me is the euro one and that is just as boring as the OEM panels. If they could add a cutom type that would be cool because I have a specific one picked out.