Max price for S2000 settled by FIA was of 168.000€, not 268.000€ like you mention.
On initial proposals it was intended to be 150.000€, but it has raised to 168.000€, with an tolerance of 15%. Obviously no manu respect it (even if they annouced it), so top spec S2000N/A prices came close, or above, 300.000€.
italiaspeed.com
Gatt: S2000 is affordable : Rallye-Info.com
RED Motorsport Ltd - World Rally Team Brochure Download
S2000 Sales Document
At the same way, the 180.000€ target price for R5 will be totally over passed, and this type of cars, even if less expensive than S2000 to mantain, will only be accesible to proteams. Amateurs will have to stay with aging N4 material or change to 2wd...