The 08 had the wider front end and plastic front bumper. The rear suspension rails were slightly different.
The original 08 motor had the best head, but only single ring pistons.
If you chose you could participate in a couple of motor updates, basically consisting of twin ring pistons and a silly low compression head.
There have been I believe either 7 or 8 fuel mapping reflashes since 08.
There was a slight change to the coolant hose routing from 08-09 too.
I think that was about it.