Bit more news from DS3 land, I've managed to make some improvements to my control issues. It's still probably a bit too twitchy to race seriously with but maybe after some more practice I can get the hang of it more, at least for fun purposes it isn't too bad (I think it's basically down to trying to emulate a 30 to 90 degree wheel turn using the limited motion of a thumbstick).
I reduced the deadzone of the thumbsticks from 12 to 2 with the MotionInJoy software and calibrated it in iRacing to be a 60 degree turning radius by holding full left for both the 90 degree angle AND 30 degree calibration then set the wheel lock limit to the minimum (180 degrees I think). Just for fun I also tried calibrating the Sixaxis motion for steering in iRacing, surprisingly it worked really well except that it was kinda difficult / weird to use just holding the controller in open air (and gas / brake was odd too) but went back to the stick setup.
Lap time wise I managed to turn about 10-15 "complete" laps of Laguna Seca in the MX-5, it's still kinda hard getting used to the controls as they are not nearly as forgiving as GT5 is in terms of correcting oversteer / spinning out and such (some of my issue is no doubt the DS3 though) so I'm not very consistent yet but I did manage to turn a couple of clean laps in the mid 1'47s, then two more low 1'46s and rounded out with a 1'45.1xx and 1'45.0xx!
Just need to get more consistent, slow down enough for turns and be as gentle as possible with the controller and I might one day try an actual race heh.