I have the Rovacom setup for my D2 TD5. Like it a lot, Its enabled me to change the locking and window options, turn on speed locking and courtesy lights etc with out a visit to the dealer each time and $100 a pop
Also has helped me find out where the 2 SRS faults I've had are occuring and enabled me to beat the dealer over the head to fix em under warranty.
Also recalibrated my ACE to allow for the heavy winch, sill armour and diff armour (much better handling now) and to recalibrate the SLS to allow for fat old me so the car sits level now
Its also nice to know I have NO fault codes on any system
Its expensive but I believe worth it, especially if you like playing with your car
Oh yes, you can also make the disco leap about like one of those stupid show cars using the SLS manual controls (albeit a lot slower than theres do)
Also found out that the D2 has a Police mode setting, but nobody seems to know what it does!!!