Yeah, I was the 200SXOC Chairman, Ive owned 9 or 10 and am fairly familiar with them ..........
The link for the car scorp has bought is now gone so I cant comment on it specifically but ............
Errr ......... was it a while ago you had one? The biggest issue these days is rust - every S14 in the UK will either have some rust on the sills or had the sills done, strut tops (front and back) and chassis rails are also favourites, check jacking points too as they are prone to collapse after a bit of red lovin. Arches and other bits go like other cars, weve been seeing some issues with inner wheel arches recently too.
Enginewise, VVT rattle seems to be affecting lots of cars, IIRC its about £200-300 to fix. Turbo gaskets go all the time and are cheap but a PITA to sort, turbos are usually good for 100K+ is not ragged to death, they are fairly cheap to replace too but its worth a check for smoking on idle or boost. Standard suspension is @*!# so youll want to change if you havent already and ARB's do wonders for body roll. Gearboxes are solid at standard power and clutches tend to last too.
Not difficult to take one to around 400hp but do lows and wheels first, standard Kouki or Zenki with right fitment look spot on:
And the SXOC is probably the best source of knowledge on the car globally, there is pretty much nothing that hasnt been done at some point. Enjoy!