Hi,
well what I can tell you is that on my car the 68mm throttlebody wasn't a good setup. The ECU kept throwing P1514 at me when putting a higher than mild load on the engine.
Just this evening reverted back to the 58mm TB and all seems happy again. So I don't know exactly what the issue is, but it looks like the ECU isn't happy comparing the throttle opening to the MAP value.
It could be that it is possible to change this when mapping the ECU, however I (still) have no idea which variables are changable when mapping the ECU.
I'm driving the car to work the rest of the week to get the ECU up to speed with the new manifold (judging from the OBD readings it is still adjusting). If everything is ok I'll post up the results somewhere in the weekend (including the partnumbers I used).
Cheers,
Mark