The kit went together fairly well, even though it strictly says that the job is not for "do it yourselfers". Well, I guess they have to say that to try to discourage people from avoiding the dealer. However, if you're reasonably handy and typically work on the car or other hardware, you may be able to do this too. Follow the instructions, as they lay out all of the needed steps, and there are a lot of them. I took about 5 hours total, but that includes everything from gathering tools at the beginning, taking quick breaks, and waxing everything when done.
You can see from the photo on the right that the new side-sill is not that much lower to the ground compared to the original. (They are kind of upside-down in the photo.) The new one is noticeably wider, however. Where the stock sills curve under the car, the new ones stick out.
The front and rear pieces are a bit lower to the ground than stock, perhaps by about 1".
Having tools that allow you to go around corners can be a big help, as well as having all of the needed sockets and bits.
I don't have many pictures of the actual installation because I thought it was fairly straightforward, and I don't think photos would really help a whole lot.
This is the car with just the front lip spoiler:
This is with the full body kit:
The look is not overly-aggressive. It's clean, with lines that follow the lines already in the car.