I think you are correct about the FPC in the previous race car. This is the GT4 which employs a CPC. However, from what I've researched, it uses a lot of Voodoo components, at least the block & heads. I imagine the forged Al. pistons and forged steel rods with fracture split caps, too, but that's just my speculation. Yes, seam welding surely adds to the stiffness and durability of the chassis.