Hi and welcome to SIDC. If you can find a WRX with PPP and no other mods, you'll not be disappointed - the PPP cost about £1,700 when new, but doesn't appear to affect buying prices very much. In my opinion, best to choose this route, rather than chance a car with all sorts of non standard mods - you can always do own bits and pieces later and to your choice, should you wish.
John