With an MT5/MT6, tick over is definitely influenced, and light throttle position information to the engine ECU is altered.
Additionally, with AT4's the overdrive function can become 'dithery', and I suspect torque converter lock is influenced too.
N/A UK (export) spec engines operate using MAF, and J spec operates using MAP.
Because of this, I expected to find that the settings would be different, but have also learned that the TT settings are different too.
Until now, we have only had workshop manuals with the export spec settings, and this information has been hiding in, never before translated J spec workshop manuals.
With the amount of J spec Supra's now over here, this 'snippet' must be useful to some, I am just one of them.
Setting the sensor to the correct position is a 1-minute job; so surely, it would be foolish not too.
Stefan and his pals at Mr T HQ have researched and translated this technical detail especially at my request, and we have shared this information with others who may be interested on here.
Personally, I am very grateful for this, 'beyond the call of duty' service from Stefan and Willem in Belgium and A N Others in Japan.
Thank you very much.