Given the design and age of the 18R-C its very likely that this motor will produce less power than the standard engine the CT12's come from. Its all custom anyway you look at it so why use these small turbo's ?
A twin turbo 18RC will sound Hollywood to anyone that does not know Toyota engines, but to us, it would be a case of "Why waste your time, money and effort when so much better is available for less ?".