The Munich marque vehemently opposed the FIA's imposition of a smaller engine for 2006, but last week - with Honda - pulled out of a three-way (also involving Mercedes-Benz) threat of arbitration.
Theissen, the motor sport director, said in an interview that the change in engine concept has caused 'high pressure' and a cost increase at BMW.
He revealed: "The development programme had to be condensed, (but) we will successfully solve this task."
Mario, meanwhile, supports the new-for-2005 rule mandating one engine to last for two grands prix. The German said the 'peak' regarding the cost of being a F1 engine maker 'is in the past.' -GMM