The Dinan B4x/B58 heat exchanger for the BMW G2x/G4x and Toyota A9x Supra assists in improving overall charge cooling using a more robust core (45mm thick Dinan core vs. 26.75mm thick OEM core) that wields 68% more heat transfer surface area for improved cooling capacity. The significant increase in core thickness and full-size end tanks contribute to the overall thermal mass (ability to absorb, store, and release heat) improvement beyond the OEM setup. With up to a nearly 12º reduction in charge air temps recorded over stock the Dinan heat exchanger is ready, and able, to assist in extending your vehicles ability to deliver maximum performance time and time again for your driving enjoyment!