Doing any gymkhana whatsoever is no longer mandatory to progress in the singleplayer Career.
Made this some years ago. It changes the career progression so that any event that would need to be unlocked by doing a gymkhana event (even the gymkhana tutorials) is instead unlocked by whatever the last actual non-gymkhana race was. Only tested it on the Steam version of Dirt 3: Complete edition.
The files belong in \DiRT 3 Complete Edition\database\
rename or backup the old files if you want.
Hoping someone will find this handy.