I'm driving a lovely 2.2 JTS GT at the moment (on loan), dont notice it being too bad off the line.
You do need to finesse the clutch a bit but nothing to funny I thought.
It is a little gutless low down in second, but I think 1st is very Zingy
The sound isn't quite as cultured as the T-spark but it has a pleasant enough burble, and certainly better than most modern mainstream 4 cylinder cars.
BTW did you consider posting your ECU to Jano, after discussion fo course
This was possible for GTA ECUs at least, but the remapping process could be different for JTS ECUs.