Turbo Boost: Instant Acceleration Explained

Hello,

I drive a Fiat Bravo 1.9 MJet 16V CR-Diesel from 2007 with 108,000 km on the odometer.
"I've noticed for some time that the power delivery isn't as smooth as it used to be. When accelerating hard, the turbo kicks in almost at 1800 RPM. Below that, not much happens."

No errors stored, no smoke, common VTG turbo. The DPF has been regenerating relatively frequently lately, which makes me think it might be related to the EGR valve.

Does anyone have any ideas, or should we just wait for MSTG to get in touch?