+1 for the computer being out, if injection calibration and rail pressure maps have being touched, you'll be way out.
7 mins for a remap, it must be a world record.... it takes 40-45 minutes to read the map....
They must have injected one they had in their database, once they saw that HW & SW nº matched, one they'd done earlier (you know like the cooking programs)
But if you like it good for you.
My was reprogged too, by a pro, EGR off but DPF still on, I found it a bit too violent for my liking too much like a Golf/Audi so I got the soft and the flashing equipment and reworked his map slightly, much better now, but not exactly to my liking yet, have to mod some more.
To come back to the SLUGGINESS, I rekon the EGR pb, if as you say it is notchy = NO GOOD.
Get them to reprog without EGR. Don't know why they did not propose it in the 1st place.
It saves on the hassle of all that tar collecting on the SWIRLS