I don't think going to a WRX will satisfy you enough after a Zed I'm afraid, especially if you have an Octavia. I think you will get bored of the WRX much quicker and despite the performance being similar, the whole experience and theatre that you get with a Zed (RWD, 2 seater etc.) far outweighs it. Despite the Scooby having 4WD and turbo, the difference is not enough to make the change. An STi might be but I would still test drive first.
Unless he gets a posh one I've obviously got the chav version lol