The updates are being carried out by the Nissan High Performance Centre "Autohaus Broemmler". I suppose, but the article does not give any indications, that if it is done in cooperation with Nissan Germany, otherwise they might not be allowed to use that name. This would also mean that normally guarantee would apply, but also this is not being referred to in the article.
(I have already seen another tuned version by Cobra, giving 620 BHP).
"I find the whole business of religion profoundly interesting, but it does mystify me that otherwise intelligent people take it seriously." Douglas Adams