olli:

Very disappointing for race for Porsche overall and a disaster for the works Team Manthey!

I wonder if the GT3 R has the potential to become competitive at all under the current BoP rules. 

Yes, very dissapointing.

Sure , the car has the potential to become competitive...if given the right BoP. I believe they were running with 34.5mm restrictors on each side. If they were increased to say 36mm on each side, it could have been an excellent Porsche & Mercedes battle.