Yep, they run rich as fook in boost when mapped. Stock progressively drops from 14.7 AFR > 14 > 13.8 > 12.8 in boost. Remaps just drop the anvil down from 14.7 > 12-11.5 immediately for arse covering richness. Thankfully petrol engines make the same power over a wide range of AFRs, but it's just wasting fuel if you see tons of smoke out the back. VW designed the engine to run relatively lean in boost. It's just sh*t mapping.
Where you will notice it the most is holding the rpm in 4th or 5th around 3500rpm waiting for a rapid over take, floor it, and you're rolling coal out the back.