is the 156 TS flywheel the same as the 147 TS?

just a question, i been offered a titanium flywheel made as a one off for a 156/GTV twin spark (brand new, never fitted) for a hell of a good price. supposedly 40% lighter than steel but just as strong? questions, will it fit my 2.0TS selespeed 147 and what benefits would it give me? i understand a lighter flywheel allows the engine to run easier (less load) and therfore improves performance? he needs to know if i want it by the end of the week so any input qould be greatly appreciated.

many thanks.

M