You can always try I suppose, I paid a specialist performance centre whom do these types of things everyday and use several coding groups from around the world...even they were dumbfounded at the complexity of these ECU's.
I virtually spoke to every specialist performance tuning group I could find and all said there is no way to tune these cars via the OBD port, I ended up going with RPW as they've worked with Hyundai's and Mitsubishi's since the early days but they were still limited in what they could find/decode.
Even going the 3rd party ECU route would have been a nightmare at this stage in time as things like the electronic steering and such wont pair up yet, they're still a year behind in solving them.
Much easier to just go with the RaceChip imo as they've already done the hard yards on the diesels but if you've got the talent and don't mind stuffing an ECU if it fails then by all means give it your best shot , keep us informed on your progress