Baseline (Widescreen) Solution & Issues
Native.
The game will initially run at your native res. In-game graphic options can be found "outside", on the far right.
Settings are saved in My Documents\My Games\DiRT2\hardwaresettings\hardware_settings_config.xml which can be edited in Notepad.
Ultra/Super-Wide (21:9/32:9) Specific Solution & Issues
Eyefinity / Surround Specific Solution & Issues
Native, Hor+ gameplay.
HUD: scales correctly, centered
Menu interface & loading screens: Hor+
Real-time cutscenes: Hor+
Fullscreen videos: stretched
4k UHD Specific Solution & Issues