Perennial Porsche GT3 challenger Manthey has announced it will enter the five-race IMSA Michelin Endurance Cup for the first time, fielding two Porsche 911 GT3 Rs.Manthey will enter its famous ‘Grello’ Porsche, the No. 911, in the GTD PRO category, while the No. 912 Porsche will compete in GTD, with...