From the description the car seems mildly modified...... not too sure what 'etc...' accessories includes. The engine seems stock as well as the turbo (hopefully both were not replaced!!).
High fun factor (as with most turbo cars) and a seemingly practical performance car.
High on fuel consumption i suspect as the ECU is upgraded (should be mapping for higher performance, dun think its to map the car for better fuel economy!!!) as well as exhuast.
Pricewise, look around a little, direct sellers might sell it lower. Remember though, unfortunately aftermarket parts adds no absolute when scrapping the car, pay more if you really want and know what the parts are worth (at the buyers expense) and even then.......the price should not exceed market rate.
My take on performance car with aftermarket parts: The owner will need alot of time and passion for the car. You will look forward to drive the car every single time and the car will be a headache for you every once in a while, kinda like a passionate love affair!!!! haha!!!

P.S. Bring someone along with experience on these cars and parts when buying the car and dun jump onto buying it just because its rare and looks great. A better car could always be just around the corner!!! Cheers!!!