Sounds like a good lad, give him my best wishes. If he's heading for University go to Coventry for the best automotive design courses in the world. If he wants to learn at home and fool around then there are plenty of resources online to play with 3D design.
I'm self-taught, just the basics to show my concept but learnt using Alias Automotive Studio (recommended to me by the Univestiry a few years ago). It needs a good sturdy computer (mine just burnt out with all the strain, so I need to find money for a new set) but there is a free educational licence from Autodesk.com to download (gigabytes of application) and play with if he wants to get up to the professional end (not for the faint-hearted, needs a lot of time and patience). He'll need to search their web site for the Educational section.
As for the current WRX. I believe it can be tweaked and tuned and restyled to make a stonkingly pretty performer with new nose, grills, lights, diffuser and a few other details (hundreds of extra horses under the bonnet). Currently just trying to raise the money for the first step.