Make sure there's not excessive dust, dirt or grime on the contact surfaces. The double sided tape should be an aid to keeping the kit on, not the only things that attaches it to the car. Thus, you shouldn't need to worry about it TOO badly.
When you install, do it at your friend's shop. It'll be a lot easier than futzing around with it in your driveway. Make sure the kit is professionally painted also. Last thing you want are cracks and peels in the paint. Good luck. Post some pics when you're pau.