I've had it confirmed that 125/132/147/155TSI engines are identical - only difference is the tune.
Power curves are the same except the lower output engines are capped.
It drives fine just down on others "claimed" times. I will get my hands on some proper GPS timing equipment and do some more scientific runs (rather than rely on AutoPolar FIS+ chrono function). At least that way I'll run both against each other and cross-reference the results.