CSF F97 X3M / F98 X4M (S58) High Performance Heat Exchanger and Transmission Cooler ModuleCSF F97 X3M F98 X4M (S58) High Performance Heat Exchanger and Transmission Cooler Module Part # 8331 CSF began designing the Heat Exchanger for the X3M X4M using all the experience and data gathered from the entire G8X Cooling Suite. The first hurdle in designing a Front Mount Heat Exchanger for these vehicles was the space constraints. The X3M and X4M use a different transmission oil cooler than the G8X models that restricted increasing the size of