I did the splitter on my 4200 a while back- its quite a faff but easy enough to do.
You'll need to do repairs to the panels after, as it leaves holes behind. Youre going to find the front bumper support has rotted away and in need of replacing. And the fixings can prove challenging !
The undertay will likely not transfer like for like, albeit they are the same part numbers...
I replaced the undertray for new, and the car resprayed. Looks mint.
I personally think the surf boards look like a Halfords after thought ( which they are ) resulting in a kind of "Liberty" chav naffness I associate with pimps and tweekers.... Each to their own, I s'pose !