The Japs do do things properly, but this car isnt meant to be a drag car or a huge horsepower machine, its target with the tune has been acclomplished. Anybody who drives the car can vouch that at this current tune, the brakes do a good job, as does the suspension...but obviously if you wanted to tune it further, you can.
When modifying any car, we can all say "this needs to be done" and "that needs to be done to make it a good car" but its all a matter of opinion and what your personal aim for the car is.
It's not a stock car with a big turbo kit on, its a stock car with a small turbo, only running 0.35bar, which gives it an excellent drive with plenty more torque and a "feel good" factor. The mods you have listed above would be for somebody wanting to create a high power monster EK9, which is all fine, but not everybody wants that...actually this seems to be too modified for most already.
As you have stated, to get to a similar tune to the "quickest EK9 in the UK", you would need a further £4k+, lets even say £6k, that would equate to £13,800....which is A LOT less than the £20k spent on the other EK9 to get there. This is good value for money as it is and the price has already been dropped from £8250, which was a good deal then, if you are serious, come to view the car and we can negotiate then if you like, or you may not feel the need as it you will realise how good value for money it is.
Documentation: Auction sheet, MOT, V5, Service information (doesnt use the same oil and plugs), spec list (currently on my site and here anyway)
That is crazy....never done before. 
