With my 6mt, she'd be in lugging territory @ 1400, unless in 1-2-3 gear. And complaining pretty loudly about it too.
Say you drop to 1400 RMP while in 6 gear. Dont expect to be able to accelerate rapidly while staying in that gear - it will take forever, you'd have to downshift to 3 or 4th gear.
Now, in 1st gear, even @ 800 RPM, she'd have enough torque to not only keep moving forward @ ~5mph, but also to get going (with real gentle clutch release ). Even in 2nd gear you could that, but it will be borderline stall territory.
Doing 75MPH, at 2100 RPM in 6th, she has enough torque for crisp and safe passing at 85-90MPH and even toward 100, seemingly effortlessly. Wont win any races, but she's got what it takes.
Low RPMs simply dont supply enough exhaust volume to spool up the turbo and she's air starved. Accelerating out of forced and fixed (via MT) lugging condition is nasty, as they can only squirt more diesel and there's not enough air to burn it all. Guess what traps the un-burned hydrocarbons ?
With autos, they force downshift which gets the RPM up, which produces more exhaust which spools up the turbo which gets the air engine needs for max power.