It is not uncommon to swap an FD3S with a 20B-REW nor even in early 2000’s. However, it is a different story when it comes to triple turbo specifications and Grand Slam PRO Machida was the creator of this amazing tune. All turbines are HKS GT2835R (I ran one of these in my old R32 RB20DET and it was an amazing turbo delivering power at a high range of rpms).
Due to the exhaust layout, the three turbines are arranged vertically through the original exhaust manifold. The engine body has been ported with an emphasis on intermediate torque, and of course talking about RX7’s apex seals were replaced.