Aj6/16 Manual Transmission Swap

Hello everyone, I’m currently building a XJSR6 using the XJR6 engine from an x300 XJR. I was just wondering what people over in America do if anyone has done one before. I’m in California and it is very difficult to source a getrag gearbox. If anyone has done the swap please let me know what gearbox you used. I’m thinking of using a tremec gearbox or maybe a Toyota Supra 5 speed.