Here is a really good mod which raises the difficulty of the AI. Makes for much tighter racing and harder to qualify on pole.
Simply backup your original DATA.MIX file (i renamed my to DATAORIGINAL.MIX) then place the file inside the RAR into your MXGP installation folder.

http://www.racedepartment.com/threads/realistic-difficulty.98696/ << Thread to original MOD

http://www.racedepartment.com/downloads/realistic-difficulty.4755/download?version=7282 <<<< DOWNLOAD LINK


Thanks to Filolaos for this.