I tried running the stock motor that came with my new S-750 bike last night and I found out that it is a stock non-X version. In fact, when I pressed the Turbo button and tried the throttle, the motor did not increase in RPMs at all. Both settings were around 260 RPM. I'm disappointed, however, I'm still overjoyed that the new unmounted motor IS an X version. I've got a lead on a spoke and rim set for the TF motor out in California and hopefully, will be able to get that and mount my new X motor.
I'm now also hoping to buy a throttle and console for the TF to fit to my M-750 which I haven't even started working on yet!